/*
 * Copyright (c) 2004-2009 Sergey Lyubka
 * Portions Copyright (c) 2009 Gilbert Wellisch
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 *
 * $Id: mongoose.c 446 2009-07-08 21:06:56Z valenok $
 */

#if defined(_WIN32)
#define _CRT_SECURE_NO_WARNINGS	/* Disable deprecation warning in VS2005 */
#endif /* _WIN32 */

#ifndef _WIN32_WCE /* Some ANSI #includes are not available on Windows CE */
#include <sys/types.h>
#include <sys/stat.h>
#include <errno.h>
#include <signal.h>
#include <fcntl.h>
#endif /* !_WIN32_WCE */

#include <time.h>
#include <stdlib.h>
#include <stdarg.h>
#include <assert.h>
#include <string.h>
#include <ctype.h>
#include <limits.h>
#include <stddef.h>
#include <stdio.h>

#if defined(_WIN32)		/* Windows specific #includes and #defines */
#define	_WIN32_WINNT	0x0400	/* To make it link in VS2005 */
#include <windows.h>

#ifndef _WIN32_WCE
#include <process.h>
#include <direct.h>
#include <io.h>
#else /* _WIN32_WCE */
/* Windows CE-specific definitions */
#include <winsock2.h>
#define NO_CGI	/* WinCE has no pipes */
#define NO_SSI	/* WinCE has no pipes */

#define FILENAME_MAX	MAX_PATH
#define BUFSIZ		4096
typedef long off_t;

#define errno			GetLastError()
#define strerror(x)		_ultoa(x, (char *) _alloca(sizeof(x) *3 ), 10)
#endif /* _WIN32_WCE */

#define EPOCH_DIFF	0x019DB1DED53E8000 /* 116444736000000000 nsecs */
#define RATE_DIFF	10000000 /* 100 nsecs */
#define MAKEUQUAD(lo, hi)	((uint64_t)(((uint32_t)(lo)) | \
				((uint64_t)((uint32_t)(hi))) << 32))
#define	SYS2UNIX_TIME(lo, hi) \
	(time_t) ((MAKEUQUAD((lo), (hi)) - EPOCH_DIFF) / RATE_DIFF)

/*
 * Visual Studio 6 does not know __func__ or __FUNCTION__
 * The rest of MS compilers use __FUNCTION__, not C99 __func__
 */
#if defined(_MSC_VER) && _MSC_VER < 1300
#define	STRX(x)			#x
#define	STR(x)			STRX(x)
#define	__func__		"line " STR(__LINE__)
#else
#define	__func__		__FUNCTION__
#endif /* _MSC_VER */

#define	ERRNO			GetLastError()
#define	NO_SOCKLEN_T
#define	SSL_LIB			"ssleay32.dll"
#define	CRYPTO_LIB		"libeay32.dll"
#define	DIRSEP			'\\'
#define	IS_DIRSEP_CHAR(c)	((c) == '/' || (c) == '\\')
#define	O_NONBLOCK		0
#define	EWOULDBLOCK		WSAEWOULDBLOCK
#define	_POSIX_
#define UINT64_FMT		"I64"

#define	SHUT_WR			1
#define	snprintf		_snprintf
#define	vsnprintf		_vsnprintf
#define	sleep(x)		Sleep((x) * 1000)

#define	popen(x, y)		_popen(x, y)
#define	pclose(x)		_pclose(x)
#define	close(x)		_close(x)
#define	dlsym(x,y)		GetProcAddress((HINSTANCE) (x), (y))
#define	RTLD_LAZY		0
#define	fseeko(x, y, z)		fseek((x), (y), (z))
#define	write(x, y, z)		_write((x), (y), (unsigned) z)
#define	read(x, y, z)		_read((x), (y), (unsigned) z)
#define	flockfile(x)		(void) 0
#define	funlockfile(x)		(void) 0

#ifdef HAVE_STRTOUI64
#define	strtoull(x, y, z)	_strtoui64(x, y, z)
#else
#define	strtoull(x, y, z)	strtoul(x, y, z)
#endif /* HAVE_STRTOUI64 */

#if !defined(fileno)
#define	fileno(x)		_fileno(x)pid_tt
#endif /* !fileno MINGW #defines fileno */

typedef HANDLE pthread_mutex_t;
typedef HANDLE pthread_cond_t;
typedef DWORD pthread_t;
typedef HANDLE pid_tt;

struct timespec
{
    long tv_nsec;
    long tv_sec;
};

static int pthread_mutex_lock(pthread_mutex_t *);
static int pthread_mutex_unlock(pthread_mutex_t *);

#if defined(HAVE_STDINT)
#include <stdint.h>
#else
typedef unsigned int		uint32_t;
typedef unsigned short		uint16_t;
#if _MSC_VER > 1200
typedef unsigned __int64	uint64_t;
#else
/* VC6 cannot cast double to unsigned __int64, needed by print_dir_entry() */
typedef __int64	uint64_t;
#endif /* _MSC_VER */
#endif /* HAVE_STDINT */

/*
 * POSIX dirent interface
 */
struct dirent
{
    char	d_name[FILENAME_MAX];
};

typedef struct DIR
{
    HANDLE			handle;
    WIN32_FIND_DATAW	info;
    struct dirent		result;
} DIR;

#else				/* UNIX  specific	*/
#include <sys/wait.h>
#include <sys/socket.h>
#include <sys/select.h>
#include <sys/mman.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <sys/time.h>

#include <pwd.h>
#include <unistd.h>
#include <dirent.h>
#include <dlfcn.h>
#include <pthread.h>
#define	SSL_LIB			"libssl.so"
#define	CRYPTO_LIB		"libcrypto.so"
#define	DIRSEP			'/'
#define	IS_DIRSEP_CHAR(c)	((c) == '/')
#define	O_BINARY		0
#ifdef _UDT_
#define	closesocket(a)		UDT::close(a)
#else
#define	closesocket(a)		close(a)
#endif
#define	mg_fopen(x, y)		fopen(x, y)
#define	mg_mkdir(x, y)		mkdir(x, y)
#define	mg_remove(x)		remove(x)
#define	mg_rename(x, y)		rename(x, y)
#define	mg_getcwd(x, y)		getcwd(x, y)
#define	ERRNO			errno
#define	INVALID_SOCKET		(-1)
#define UINT64_FMT		"ll"
typedef int SOCKET;

#endif /* End of Windows and UNIX specific includes */


#include "mongoose.h"
#include "udt.h"
#define	MONGOOSE_VERSION	"2.8"
#define	PASSWORDS_FILE_NAME	".htpasswd"
#define	CGI_ENVIRONMENT_SIZE	4096
#define	MAX_CGI_ENVIR_VARS	64
#define	MAX_REQUEST_SIZE	8192
#define	MAX_LISTENING_SOCKETS	10
#define	MAX_CALLBACKS		20
#define	ARRAY_SIZE(array)	(sizeof(array) / sizeof(array[0]))
#define	UNKNOWN_CONTENT_LENGTH	((uint64_t) ~0)
#define	DEBUG_MGS_PREFIX	"*** Mongoose debug *** "

#if defined(DEBUG)
#define	DEBUG_TRACE(x) do {printf x; putchar('\n'); fflush(stdout);} while (0)
#else
#define DEBUG_TRACE(x)
#endif /* DEBUG */

/*
 * Darwin prior to 7.0 and Win32 do not have socklen_t
 */
#ifdef NO_SOCKLEN_T
typedef int socklen_t;
#endif /* NO_SOCKLEN_T */

#if !defined(FALSE)
enum {FALSE, TRUE};
#endif /* !FALSE */

typedef int bool_t;
typedef void * (*mg_thread_func_t)(void *);

static const char *http_500_error = "Internal Server Error";

/*
 * Snatched from OpenSSL includes. I put the prototypes here to be independent
 * from the OpenSSL source installation. Having this, mongoose + SSL can be
 * built on any system with binary SSL libraries installed.
 */
typedef struct ssl_st SSL;
typedef struct ssl_method_st SSL_METHOD;
typedef struct ssl_ctx_st SSL_CTX;

#define	SSL_ERROR_WANT_READ	2
#define	SSL_ERROR_WANT_WRITE	3
#define SSL_FILETYPE_PEM	1
#define	CRYPTO_LOCK		1

/*
 * Dynamically loaded SSL functionality
 */
struct ssl_func
{
    const char	*name;		/* SSL function name	*/
    void		(*ptr)(void);	/* Function pointer	*/
};

#define	SSL_free(x)	(* (void (*)(SSL *)) ssl_sw[0].ptr)(x)
#define	SSL_accept(x)	(* (int (*)(SSL *)) ssl_sw[1].ptr)(x)
#define	SSL_connect(x)	(* (int (*)(SSL *)) ssl_sw[2].ptr)(x)
#define	SSL_read(x,y,z)	(* (int (*)(SSL *, void *, int)) 		\
				ssl_sw[3].ptr)((x),(y),(z))
#define	SSL_write(x,y,z) (* (int (*)(SSL *, const void *,int))		\
				ssl_sw[4].ptr)((x), (y), (z))
#define	SSL_get_error(x,y)(* (int (*)(SSL *, int)) ssl_sw[5])((x), (y))
#define	SSL_set_fd(x,y)	(* (int (*)(SSL *, SOCKET)) ssl_sw[6].ptr)((x), (y))
#define	SSL_new(x)	(* (SSL * (*)(SSL_CTX *)) ssl_sw[7].ptr)(x)
#define	SSL_CTX_new(x)	(* (SSL_CTX * (*)(SSL_METHOD *)) ssl_sw[8].ptr)(x)
#define	SSLv23_server_method()	(* (SSL_METHOD * (*)(void)) ssl_sw[9].ptr)()
#define	SSL_library_init() (* (int (*)(void)) ssl_sw[10].ptr)()
#define	SSL_CTX_use_PrivateKey_file(x,y,z)	(* (int (*)(SSL_CTX *, \
		const char *, int)) ssl_sw[11].ptr)((x), (y), (z))
#define	SSL_CTX_use_certificate_file(x,y,z)	(* (int (*)(SSL_CTX *, \
		const char *, int)) ssl_sw[12].ptr)((x), (y), (z))
#define SSL_CTX_set_default_passwd_cb(x,y) \
	(* (void (*)(SSL_CTX *, mg_spcb_t)) ssl_sw[13].ptr)((x),(y))
#define SSL_CTX_free(x) (* (void (*)(SSL_CTX *)) ssl_sw[14].ptr)(x)

#define CRYPTO_num_locks() (* (int (*)(void)) crypto_sw[0].ptr)()
#define CRYPTO_set_locking_callback(x)					\
		(* (void (*)(void (*)(int, int, const char *, int)))	\
	 	crypto_sw[1].ptr)(x)
#define CRYPTO_set_id_callback(x)					\
	(* (void (*)(unsigned long (*)(void))) crypto_sw[2].ptr)(x)

/*
 * set_ssl_option() function when called, updates this array.
 * It loads SSL library dynamically and changes NULLs to the actual addresses
 * of respective functions. The macros above (like SSL_connect()) are really
 * just calling these functions indirectly via the pointer.
 */
static struct ssl_func	ssl_sw[] =
{
    {"SSL_free",			NULL
    },
    {"SSL_accept",			NULL},
    {"SSL_connect",			NULL},
    {"SSL_read",			NULL},
    {"SSL_write",			NULL},
    {"SSL_get_error",		NULL},
    {"SSL_set_fd",			NULL},
    {"SSL_new",			NULL},
    {"SSL_CTX_new",			NULL},
    {"SSLv23_server_method",	NULL},
    {"SSL_library_init",		NULL},
    {"SSL_CTX_use_PrivateKey_file",	NULL},
    {"SSL_CTX_use_certificate_file",NULL},
    {"SSL_CTX_set_default_passwd_cb",NULL},
    {"SSL_CTX_free",		NULL},
    {NULL,				NULL}
};

/*
 * Similar array as ssl_sw. These functions are located in different lib.
 */
static struct ssl_func	crypto_sw[] =
{
    {"CRYPTO_num_locks",		NULL
    },
    {"CRYPTO_set_locking_callback",	NULL},
    {"CRYPTO_set_id_callback",	NULL},
    {NULL,				NULL}
};

/*
 * Month names
 */
static const char *month_names[] =
{
    "Jan", "Feb", "Mar", "Apr", "May", "Jun",
    "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"
};

/*
 * Unified socket address. For IPv6 support, add IPv6 address structure
 * in the union u.
 */
struct usa
{
    socklen_t len;
    union
    {
        struct sockaddr	sa;
        struct sockaddr_in sin;
    } u;
};

/*
 * Specifies a string (chunk of memory).
 * Used to traverse comma separated lists of options.
 */
struct vec
{
    const char	*ptr;
    size_t		len;
};

/*
 * Structure used by mg_stat() function. Uses 64 bit file length.
 */
struct mgstat
{
    bool_t		is_directory;	/* Directory marker		*/
    uint64_t	size;		/* File size			*/
    time_t		mtime;		/* Modification time		*/
};

struct mg_option
{
    const char	*name;
    const char	*description;
    const char	*default_value;
    int		index;
    bool_t (*setter)(struct mg_context *, const char *);
};

/*
 * Numeric indexes for the option values in context, ctx->options
 */
enum mg_option_index
{
    OPT_ROOT, OPT_INDEX_FILES, OPT_PORTS, OPT_DIR_LIST, OPT_CGI_EXTENSIONS,
    OPT_CGI_INTERPRETER, OPT_CGI_ENV, OPT_SSI_EXTENSIONS, OPT_AUTH_DOMAIN,
    OPT_AUTH_GPASSWD, OPT_AUTH_PUT, OPT_ACCESS_LOG, OPT_ERROR_LOG,
    OPT_SSL_CERTIFICATE, OPT_ALIASES, OPT_ACL, OPT_UID, OPT_PROTECT,
    OPT_SERVICE, OPT_HIDE, OPT_ADMIN_URI, OPT_MAX_THREADS, OPT_IDLE_TIME,
    OPT_MIME_TYPES,
    NUM_OPTIONS
};

/*
 * Structure used to describe listening socket, or socket which was
 * accept()-ed by the master thread and queued for future handling
 * by the worker thread.
 */
struct socket
{
#ifdef _UDT_
    UDTSOCKET   sock;
#else
    SOCKET		sock;		/* Listening socket		*/
#endif
    struct usa	lsa;		/* Local socket address		*/
    struct usa	rsa;		/* Remote socket address	*/
    bool_t		is_ssl;		/* Is socket SSL-ed		*/
};

/*
 * Callback function, and where it is bound to
 */
struct callback
{
    char		*uri_regex;	/* URI regex to handle		*/
    mg_callback_t	func;		/* user callback		*/
    bool_t		is_auth;	/* func is auth checker		*/
    int		status_code;	/* error code to handle		*/
    void		*user_data;	/* opaque user data		*/
};

/*
 * Mongoose context
 */
struct mg_context
{
    int		stop_flag;	/* Should we stop event loop	*/
    SSL_CTX		*ssl_ctx;	/* SSL context			*/

    FILE		*access_log;	/* Opened access log		*/
    FILE		*error_log;	/* Opened error log		*/

    struct socket	listeners[MAX_LISTENING_SOCKETS];
    int		num_listeners;

    struct callback	callbacks[MAX_CALLBACKS];
    int		num_callbacks;

    char		*options[NUM_OPTIONS];	/* Configured opions	*/
    pthread_mutex_t	opt_mutex[NUM_OPTIONS];	/* Option protector	*/

    int		max_threads;	/* Maximum number of threads	*/
    int		num_threads;	/* Number of threads		*/
    int		num_idle;	/* Number of idle threads	*/
    pthread_mutex_t	thr_mutex;	/* Protects (max|num)_threads	*/
    pthread_cond_t	thr_cond;
    pthread_mutex_t	bind_mutex;	/* Protects bind operations	*/

    struct socket	queue[20];	/* Accepted sockets		*/
    int		sq_head;	/* Head of the socket queue	*/
    int		sq_tail;	/* Tail of the socket queue	*/
    pthread_cond_t	empty_cond;	/* Socket queue empty condvar	*/
    pthread_cond_t	full_cond;	/* Socket queue full condvar	*/

    mg_spcb_t	ssl_password_callback;
    mg_callback_t	log_callback;
};

/*
 * Client connection.
 */
struct mg_connection
{
    struct mg_request_info	request_info;
    struct mg_context *ctx;		/* Mongoose context we belong to*/
    SSL		*ssl;		/* SSL descriptor		*/
    struct socket	client;		/* Connected client		*/
    time_t		birth_time;	/* Time connection was accepted	*/
    bool_t		free_post_data;	/* post_data was malloc-ed	*/
    bool_t		embedded_auth;	/* Used for authorization	*/
    uint64_t	num_bytes_sent;	/* Total bytes sent to client	*/
};

/*
 * Print error message to the opened error log stream.
 */
static void
cry(struct mg_connection *conn, const char *fmt, ...)
{
    char	buf[BUFSIZ];
    va_list	ap;

    va_start(ap, fmt);
    (void) vsnprintf(buf, sizeof(buf), fmt, ap);
    conn->ctx->log_callback(conn, &conn->request_info, buf);
    va_end(ap);
}

/*
 * Return fake connection structure. Used for logging, if connection
 * is not applicable at the moment of logging.
 */
static struct mg_connection *
            fc(struct mg_context *ctx)
{
    static struct mg_connection fake_connection;
    fake_connection.ctx = ctx;
    return (&fake_connection);
}

/*
 * If an embedded code does not intercept logging by calling
 * mg_set_log_callback(), this function is used for logging. It prints
 * stuff to the conn->error_log, which is stderr unless "error_log"
 * option was set.
 */
static void
builtin_error_log(struct mg_connection *conn,
                  const struct mg_request_info *request_info, void *message)
{
    FILE	*fp;
    time_t	timestamp;

    fp = conn->ctx->error_log;
    flockfile(fp);

    timestamp = time(NULL);

    (void) fprintf(fp,
                   "[%010lu] [error] [client %s] ",
                   (unsigned long) timestamp,
                   inet_ntoa(conn->client.rsa.u.sin.sin_addr));

    if (request_info->request_method != NULL)
        (void) fprintf(fp, "%s %s: ",
                       request_info->request_method,
                       request_info->uri);

    (void) fprintf(fp, "%s", (char *) message);

    fputc('\n', fp);

    funlockfile(fp);
}

const char *
mg_version(void)
{
    return (MONGOOSE_VERSION);
}

static void
mg_strlcpy(register char *dst, register const char *src, size_t n)
{
    for (; *src != '\0' && n > 1; n--)
        *dst++ = *src++;
    *dst = '\0';
}

static int
lowercase(const char *s)
{
    return (tolower(* (unsigned char *) s));
}

static int
mg_strncasecmp(const char *s1, const char *s2, size_t len)
{
    int	diff = 0;

    if (len > 0)
        do
        {
            diff = lowercase(s1++) - lowercase(s2++);
        }
        while (diff == 0 && s1[-1] != '\0' && --len > 0);

    return (diff);
}

static int
mg_strcasecmp(const char *s1, const char *s2)
{
    int	diff;

    do
    {
        diff = lowercase(s1++) - lowercase(s2++);
    }
    while (diff == 0 && s1[-1] != '\0');

    return (diff);
}

static char *
mg_strndup(const char *ptr, size_t len)
{
    char	*p;

    if ((p = (char *) malloc(len + 1)) != NULL)
        mg_strlcpy(p, ptr, len + 1);

    return (p);

}

static char *
mg_strdup(const char *str)
{
    return (mg_strndup(str, strlen(str)));
}

/*
 * Like snprintf(), but never returns negative value, or the value
 * that is larger than a supplied buffer.
 * Thanks to Adam Zeldis to pointing snprintf()-caused vulnerability
 * in his audit report.
 */
static int
mg_vsnprintf(struct mg_connection *conn,
             char *buf, size_t buflen, const char *fmt, va_list ap)
{
    int	n;

    if (buflen == 0)
        return (0);

    n = vsnprintf(buf, buflen, fmt, ap);

    if (n < 0)
    {
        cry(conn, "vsnprintf error");
        n = 0;
    }
    else if (n >= (int) buflen)
    {
        cry(conn, "truncating vsnprintf buffer: [%.*s]",
            n > 200 ? 200 : n, buf);
        n = (int) buflen - 1;
    }
    buf[n] = '\0';

    return (n);
}

static int
mg_snprintf(struct mg_connection *conn,
            char *buf, size_t buflen, const char *fmt, ...)
{
    va_list	ap;
    int	n;

    va_start(ap, fmt);
    n = mg_vsnprintf(conn, buf, buflen, fmt, ap);
    va_end(ap);

    return (n);
}

/*
 * Convert string representing a boolean value to a boolean value
 */
static bool_t
is_true(const char *str)
{
    static const char	*trues[] = {"1", "yes", "true", "ja", NULL};
    int			i;

    for (i = 0; trues[i] != NULL; i++)
        if (str != NULL && mg_strcasecmp(str, trues[i]) == 0)
            return (TRUE);

    return (FALSE);
}

/*
 * Skip the characters until one of the delimiters characters found.
 * 0-terminate resulting word. Skip the rest of the delimiters if any.
 * Advance pointer to buffer to the next word. Return found 0-terminated word.
 */
static char *
skip(char **buf, const char *delimiters)
{
    char	*p, *begin_word, *end_word, *end_delimiters;

    begin_word = *buf;
    end_word = begin_word + strcspn(begin_word, delimiters);
    end_delimiters = end_word + strspn(end_word, delimiters);

    for (p = end_word; p < end_delimiters; p++)
        *p = '\0';

    *buf = end_delimiters;

    return (begin_word);
}

/*
 * Return HTTP header value, or NULL if not found.
 */
static const char *
get_header(const struct mg_request_info *ri, const char *name)
{
    int	i;

    for (i = 0; i < ri->num_headers; i++)
        if (!mg_strcasecmp(name, ri->http_headers[i].name))
            return (ri->http_headers[i].value);

    return (NULL);
}

const char *
mg_get_header(const struct mg_connection *conn, const char *name)
{
    return (get_header(&conn->request_info, name));
}

/*
 * A helper function for traversing comma separated list of values.
 * It returns a list pointer shifted to the next value, of NULL if the end
 * of the list found.
 * Value is stored in val vector. If value has form "x=y", then eq_val
 * vector is initialized to point to the "y" part, and val vector length
 * is adjusted to point only to "x".
 */
static const char *
next_option(const char *list, struct vec *val, struct vec *eq_val)
{
    if (list == NULL || *list == '\0')
    {
        /* End of the list */
        list = NULL;
    }
    else
    {
        val->ptr = list;
        if ((list = strchr(val->ptr, ',')) != NULL)
        {
            /* Comma found. Store length and shift the list ptr */
            val->len = list - val->ptr;
            list++;
        }
        else
        {
            /* This value is the last one */
            list = val->ptr + strlen(val->ptr);
            val->len = list - val->ptr;
        }

        if (eq_val != NULL)
        {
            /*
             * Value has form "x=y", adjust pointers and lengths
             * so that val points to "x", and eq_val points to "y".
             */
            eq_val->len = 0;
            eq_val->ptr = (char*)memchr(val->ptr, '=', val->len);
            if (eq_val->ptr != NULL)
            {
                eq_val->ptr++;  /* Skip over '=' character */
                eq_val->len = val->ptr + val->len - eq_val->ptr;
                val->len = (eq_val->ptr - val->ptr) - 1;
            }
        }
    }

    return (list);
}

#if !(defined(NO_CGI) && defined(NO_SSI))
/*
 * Verify that given file has certain extension
 */
static bool_t
match_extension(const char *path, const char *ext_list)
{
    struct vec	ext_vec;
    size_t		path_len;

    path_len = strlen(path);

    while ((ext_list = next_option(ext_list, &ext_vec, NULL)) != NULL)
        if (ext_vec.len < path_len &&
                mg_strncasecmp(path + path_len - ext_vec.len,
                               ext_vec.ptr, ext_vec.len) == 0)
            return (TRUE);

    return (FALSE);
}
#endif /* !(NO_CGI && NO_SSI) */

/*
 * Return TRUE if "uri" matches "regexp".
 * '*' in the regexp means zero or more characters.
 */
static bool_t
match_regex(const char *uri, const char *regexp)
{
    if (*regexp == '\0')
        return (*uri == '\0');

    if (*regexp == '*')
        do
        {
            if (match_regex(uri, regexp + 1))
                return (TRUE);
        }
        while (*uri++ != '\0');

    if (*uri != '\0' && *regexp == *uri)
        return (match_regex(uri + 1, regexp + 1));

    return (FALSE);
}

static const struct callback *
            find_callback(struct mg_context *ctx, bool_t is_auth,
                          const char *uri, int status_code)
{
    const struct callback	*cb, *found;
    int			i;

    found = NULL;
    pthread_mutex_lock(&ctx->bind_mutex);
    for (i = 0; i < ctx->num_callbacks; i++)
    {
        cb = ctx->callbacks + i;
        if ((uri != NULL && cb->uri_regex != NULL &&
                ((is_auth && cb->is_auth) || (!is_auth && !cb->is_auth)) &&
                match_regex(uri, cb->uri_regex)) || (uri == NULL &&
                                                     (cb->status_code == 0 ||
                                                      cb->status_code == status_code)))
        {
            found = cb;
            break;
        }
    }
    pthread_mutex_unlock(&ctx->bind_mutex);

    return (found);
}

/*
 * For use by external application. This sets custom logging function.
 */
void
mg_set_log_callback(struct mg_context *ctx, mg_callback_t log_callback)
{
    /* If NULL is specified as a callback, revert back to the default */
    if (log_callback == NULL)
        ctx->log_callback = &builtin_error_log;
    else
        ctx->log_callback = log_callback;
}

/*
 * Send error message back to the client.
 */
static void
send_error(struct mg_connection *conn, int status, const char *reason,
           const char *fmt, ...)
{
    const struct callback	*cb;
    char		buf[BUFSIZ];
    va_list		ap;
    int		len;

    conn->request_info.status_code = status;

    /* If error handler is set, call it. Otherwise, send error message */
    if ((cb = find_callback(conn->ctx, FALSE, NULL, status)) != NULL)
    {
        cb->func(conn, &conn->request_info, cb->user_data);
    }
    else
    {
        buf[0] = '\0';
        len = 0;

        /* Errors 1xx, 204 and 304 MUST NOT send a body */
        if (status > 199 && status != 204 && status != 304)
        {
            len = mg_snprintf(conn, buf, sizeof(buf),
                              "Error %d: %s\n", status, reason);
            cry(conn, "%s", buf);

            va_start(ap, fmt);
            len += mg_vsnprintf(conn, buf + len, sizeof(buf) - len,
                                fmt, ap);
            va_end(ap);
            conn->num_bytes_sent = len;
        }

        (void) mg_printf(conn,
                         "HTTP/1.1 %d %s\r\n"
                         "Content-Type: text/plain\r\n"
                         "Content-Length: %d\r\n"
                         "Connection: close\r\n"
                         "\r\n%s", status, reason, len, buf);
    }
}

#ifdef _WIN32
static int
pthread_mutex_init(pthread_mutex_t *mutex, void *unused)
{
    unused = NULL;
    *mutex = CreateMutex(NULL, FALSE, NULL);
    return (*mutex == NULL ? -1 : 0);
}

static int
pthread_mutex_destroy(pthread_mutex_t *mutex)
{
    return (CloseHandle(*mutex) == 0 ? -1 : 0);
}

static int
pthread_mutex_lock(pthread_mutex_t *mutex)
{
    return (WaitForSingleObject(*mutex, INFINITE) == WAIT_OBJECT_0? 0 : -1);
}

static int
pthread_mutex_unlock(pthread_mutex_t *mutex)
{
    return (ReleaseMutex(*mutex) == 0 ? -1 : 0);
}

static int
pthread_cond_init(pthread_cond_t *cv, const void *unused)
{
    unused = NULL;
    *cv = CreateEvent(NULL, FALSE, FALSE, NULL);
    return (*cv == NULL ? -1 : 0);
}

static int
pthread_cond_timedwait(pthread_cond_t *cv, pthread_mutex_t *mutex,
                       const struct timespec *ts)
{
    DWORD	status;
    DWORD	msec = INFINITE;
    time_t	now;

    if (ts != NULL)
    {
        now = time(NULL);
        msec = 1000 * (now > ts->tv_sec ? 0 : ts->tv_sec - now);
    }

    (void) ReleaseMutex(*mutex);
    status = WaitForSingleObject(*cv, msec);
    (void) WaitForSingleObject(*mutex, INFINITE);

    return (status == WAIT_OBJECT_0 ? 0 : -1);
}

static int
pthread_cond_wait(pthread_cond_t *cv, pthread_mutex_t *mutex)
{
    return (pthread_cond_timedwait(cv, mutex, NULL));
}

static int
pthread_cond_signal(pthread_cond_t *cv)
{
    return (SetEvent(*cv) == 0 ? -1 : 0);
}

static int
pthread_cond_destroy(pthread_cond_t *cv)
{
    return (CloseHandle(*cv) == 0 ? -1 : 0);
}

static pthread_t
pthread_self(void)
{
    return (GetCurrentThreadId());
}

/*
 * Change all slashes to backslashes. It is Windows.
 */
static void
fix_directory_separators(char *path)
{
    int	i;

    for (i = 0; path[i] != '\0'; i++)
    {
        if (path[i] == '/')
            path[i] = '\\';
        /* i > 0 check is to preserve UNC paths, \\server\file.txt */
        if (path[i] == '\\' && i > 0)
            while (path[i + 1] == '\\' || path[i + 1] == '/')
                (void) memmove(path + i + 1,
                               path + i + 2, strlen(path + i + 1));
    }
}

/*
 * Encode 'path' which is assumed UTF-8 string, into UNICODE string.
 * wbuf and wbuf_len is a target buffer and its length.
 */
static void
to_unicode(const char *path, wchar_t *wbuf, size_t wbuf_len)
{
    char	buf[FILENAME_MAX], *p;

    mg_strlcpy(buf, path, sizeof(buf));
    fix_directory_separators(buf);

    /* Point p to the end of the file name */
    p = buf + strlen(buf) - 1;

    /* Trim trailing backslash character */
    while (p > buf && *p == '\\' && p[-1] != ':')
        *p-- = '\0';

    /*
     * Protect from CGI code disclosure.
     * This is very nasty hole. Windows happily opens files with
     * some garbage in the end of file name. So fopen("a.cgi    ", "r")
     * actually opens "a.cgi", and does not return an error!
     */
    if (*p == 0x20 || *p == 0x2e || *p == 0x2b || (*p & ~0x7f))
    {
        (void) fprintf(stderr, "Rejecting suspicious path: [%s]", buf);
        buf[0] = '\0';
    }

    (void) MultiByteToWideChar(CP_UTF8, 0, buf, -1, wbuf, (int) wbuf_len);
}

#if defined(_WIN32_WCE)

static time_t
time(time_t *ptime)
{
    time_t		t;
    SYSTEMTIME	st;
    FILETIME	ft;

    GetSystemTime(&st);
    SystemTimeToFileTime(&st, &ft);
    t = SYS2UNIX_TIME(ft.dwLowDateTime, ft.dwHighDateTime);

    if (ptime != NULL)
        *ptime = t;

    return (t);
}

static time_t
mktime(struct tm *ptm)
{
    SYSTEMTIME	st;
    FILETIME	ft, lft;

    st.wYear = ptm->tm_year + 1900;
    st.wMonth = ptm->tm_mon + 1;
    st.wDay = ptm->tm_mday;
    st.wHour = ptm->tm_hour;
    st.wMinute = ptm->tm_min;
    st.wSecond = ptm->tm_sec;
    st.wMilliseconds = 0;

    SystemTimeToFileTime(&st, &ft);
    LocalFileTimeToFileTime(&ft, &lft);
    return (time_t)((MAKEUQUAD(lft.dwLowDateTime, lft.dwHighDateTime) -
                     EPOCH_DIFF) / RATE_DIFF);
}

static struct tm *
            localtime(const time_t *ptime, struct tm *ptm)
{
    uint64_t	t = ((uint64_t)*ptime) * RATE_DIFF + EPOCH_DIFF;
    FILETIME	ft, lft;
    SYSTEMTIME	st;
    TIME_ZONE_INFORMATION	tzinfo;

    if (ptm == NULL)
        return NULL;

    * (uint64_t *) &ft = t;
    FileTimeToLocalFileTime(&ft, &lft);
    FileTimeToSystemTime(&lft, &st);
    ptm->tm_year = st.wYear - 1900;
    ptm->tm_mon = st.wMonth - 1;
    ptm->tm_wday = st.wDayOfWeek;
    ptm->tm_mday = st.wDay;
    ptm->tm_hour = st.wHour;
    ptm->tm_min = st.wMinute;
    ptm->tm_sec = st.wSecond;
    ptm->tm_yday = 0; // hope nobody uses this
    ptm->tm_isdst = ((GetTimeZoneInformation(&tzinfo) ==
                      TIME_ZONE_ID_DAYLIGHT) ? 1 : 0);

    return ptm;
}

static size_t
strftime(char *dst, size_t dst_size, const char *fmt, const struct tm *tm)
{
    (void) snprintf(dst, dst_size, "implement strftime() for WinCE");
    return (0);
}
#endif

static int
mg_rename(const char* oldname, const char* newname)
{
    wchar_t	woldbuf[FILENAME_MAX];
    wchar_t	wnewbuf[FILENAME_MAX];

    to_unicode(oldname, woldbuf, ARRAY_SIZE(woldbuf));
    to_unicode(newname, wnewbuf, ARRAY_SIZE(wnewbuf));

    return (MoveFileW(woldbuf, wnewbuf) ? 0 : -1);
}


static FILE *
mg_fopen(const char *path, const char *mode)
{
    wchar_t	wbuf[FILENAME_MAX], wmode[20];

    to_unicode(path, wbuf, ARRAY_SIZE(wbuf));
    MultiByteToWideChar(CP_UTF8, 0, mode, -1, wmode, ARRAY_SIZE(wmode));

    return (_wfopen(wbuf, wmode));
}

static int
mg_stat(const char *path, struct mgstat *stp)
{
    int				ok = -1; /* Error */
    wchar_t				wbuf[FILENAME_MAX];
    WIN32_FILE_ATTRIBUTE_DATA	info;

    to_unicode(path, wbuf, ARRAY_SIZE(wbuf));

    if (GetFileAttributesExW(wbuf, GetFileExInfoStandard, &info) != 0)
    {
        stp->size = MAKEUQUAD(info.nFileSizeLow, info.nFileSizeHigh);
        //stp->mtime = SYS2UNIX_TIME(info.ftLastWriteTime.dwLowDateTime,
        //    info.ftLastWriteTime.dwHighDateTime);
        stp->mtime = 0;
        stp->is_directory =
            info.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY;
        ok = 0;  /* Success */
    }

    return (ok);
}

static int
mg_remove(const char *path)
{
    wchar_t	wbuf[FILENAME_MAX];

    to_unicode(path, wbuf, ARRAY_SIZE(wbuf));

    return (DeleteFileW(wbuf) ? 0 : -1);
}

static int
mg_mkdir(const char *path, int mode)
{
    char	buf[FILENAME_MAX];
    wchar_t	wbuf[FILENAME_MAX];

    mode = 0; /* Unused */
    mg_strlcpy(buf, path, sizeof(buf));
    fix_directory_separators(buf);

    (void) MultiByteToWideChar(CP_UTF8, 0, buf, -1, wbuf, sizeof(wbuf));

    return (CreateDirectoryW(wbuf, NULL) ? 0 : -1);
}

static char *
mg_getcwd(char *buf, int buf_len)
{
    wchar_t		wbuf[FILENAME_MAX], *basename;

    if (GetModuleFileNameW(NULL, wbuf, ARRAY_SIZE(wbuf)))
    {
        if ((basename = wcsrchr(wbuf, DIRSEP)) != NULL)
        {
            *basename = L'\0';
            if (WideCharToMultiByte(CP_UTF8, 0, wbuf, -1, buf,
                                    buf_len, NULL, NULL) > 0)
                return (buf);
        }
    }

    return (NULL);
}

/*
 * Implementation of POSIX opendir/closedir/readdir for Windows.
 */
static DIR *
opendir(const char *name)
{
    DIR	*dir = NULL;
    wchar_t	wpath[FILENAME_MAX];
    DWORD attrs;

    if (name == NULL)
    {
        SetLastError(ERROR_BAD_ARGUMENTS);
    }
    else if ((dir = (DIR *) malloc(sizeof(*dir))) == NULL)
    {
        SetLastError(ERROR_NOT_ENOUGH_MEMORY);
    }
    else
    {
        to_unicode(name, wpath, ARRAY_SIZE(wpath));
        attrs = GetFileAttributesW(wpath);
        if (attrs != 0xFFFFFFFF &&
                ((attrs & FILE_ATTRIBUTE_DIRECTORY) == FILE_ATTRIBUTE_DIRECTORY))
        {
            (void) wcscat(wpath, L"\\*");
            dir->handle = FindFirstFileW(wpath, &dir->info);
            dir->result.d_name[0] = '\0';
        }
        else
        {
            free(dir);
            dir = NULL;
        }
    }

    return (dir);
}

static int
closedir(DIR *dir)
{
    int result = 0;

    if (dir != NULL)
    {
        if (dir->handle != INVALID_HANDLE_VALUE)
            result = FindClose(dir->handle) ? 0 : -1;

        free(dir);
    }
    else
    {
        result = -1;
        SetLastError(ERROR_BAD_ARGUMENTS);
    }

    return (result);
}

struct dirent *
            readdir(DIR *dir)
{
    struct dirent *result = 0;

    if (dir)
    {
        if (dir->handle != INVALID_HANDLE_VALUE)
        {
            result = &dir->result;
            (void) WideCharToMultiByte(CP_UTF8, 0,
                                       dir->info.cFileName, -1, result->d_name,
                                       sizeof(result->d_name), NULL, NULL);

            if (!FindNextFileW(dir->handle, &dir->info))
            {
                (void) FindClose(dir->handle);
                dir->handle = INVALID_HANDLE_VALUE;
            }

        }
        else
        {
            SetLastError(ERROR_FILE_NOT_FOUND);
        }
    }
    else
    {
        SetLastError(ERROR_BAD_ARGUMENTS);
    }

    return (result);
}

#define	set_close_on_exec(fd)	/* No FD_CLOEXEC on Windows */

static int
start_thread(struct mg_context *ctx, mg_thread_func_t func, void *param)
{
    HANDLE	hThread;

    ctx = NULL;	/* Unused */

    hThread = CreateThread(NULL, 0,
                           (LPTHREAD_START_ROUTINE) func, param, 0, NULL);

    if (hThread != NULL)
        (void) CloseHandle(hThread);

    return (hThread == NULL ? -1 : 0);
}

static HANDLE
dlopen(const char *dll_name, int flags)
{
    wchar_t	wbuf[FILENAME_MAX];

    flags = 0; /* Unused */
    to_unicode(dll_name, wbuf, ARRAY_SIZE(wbuf));

    return (LoadLibraryW(wbuf));
}

#if !defined(NO_CGI)
static int
kill(pid_tt pid, int sig_num)
{
    (void) TerminateProcess(pid, sig_num);
    (void) CloseHandle(pid);
    return (0);
}

static pid_tt
spawn_process(struct mg_connection *conn, const char *prog, char *envblk,
              char *envp[], int fd_stdin, int fd_stdout, const char *dir)
{
    HANDLE	me;
    char	*p, *interp, cmdline[FILENAME_MAX], line[FILENAME_MAX];
    FILE	*fp;
    STARTUPINFOA		si;
    PROCESS_INFORMATION	pi;

    envp = NULL; /* Unused */

    (void) memset(&si, 0, sizeof(si));
    (void) memset(&pi, 0, sizeof(pi));

    /* XXX redirect CGI errors to the error log file */
    si.cb		= sizeof(si);
    si.dwFlags	= STARTF_USESTDHANDLES | STARTF_USESHOWWINDOW;
    si.wShowWindow	= SW_HIDE;

    me = GetCurrentProcess();
    (void) DuplicateHandle(me, (HANDLE) _get_osfhandle(fd_stdin), me,
                           &si.hStdInput, 0, TRUE, DUPLICATE_SAME_ACCESS);
    (void) DuplicateHandle(me, (HANDLE) _get_osfhandle(fd_stdout), me,
                           &si.hStdOutput, 0, TRUE, DUPLICATE_SAME_ACCESS);

    /* If CGI file is a script, try to read the interpreter line */
    interp = conn->ctx->options[OPT_CGI_INTERPRETER];
    if (interp == NULL)
    {
        line[2] = '\0';
        (void) mg_snprintf(conn, cmdline, sizeof(cmdline), "%s%c%s",
                           dir, DIRSEP, prog);
        if ((fp = fopen(cmdline, "r")) != NULL)
        {
            (void) fgets(line, sizeof(line), fp);
            if (memcmp(line, "#!", 2) != 0)
                line[2] = '\0';
            /* Trim whitespaces from interpreter name */
            for (p = &line[strlen(line) - 1]; p > line &&
                    isspace(*p); p--)
                *p = '\0';
            (void) fclose(fp);
        }
        interp = line + 2;
    }

    if ((p = (char *) strrchr(prog, '/')) != NULL)
        prog = p + 1;

    (void) mg_snprintf(conn, cmdline, sizeof(cmdline), "%s%s%s",
                       interp, interp[0] == '\0' ? "" : " ", prog);

    (void) mg_snprintf(conn, line, sizeof(line), "%s", dir);
    fix_directory_separators(line);

    DEBUG_TRACE((DEBUG_MGS_PREFIX "%s: Running [%s]", __func__, cmdline));
    if (CreateProcessA(NULL, cmdline, NULL, NULL, TRUE,
                       CREATE_NEW_PROCESS_GROUP, envblk, line, &si, &pi) == 0)
    {
        cry(conn, "%s: CreateProcess(%s): %d",
            __func__, cmdline, ERRNO);
        pi.hProcess = (pid_tt) -1;
    }
    else
    {
        (void) close(fd_stdin);
        (void) close(fd_stdout);
    }

    (void) CloseHandle(si.hStdOutput);
    (void) CloseHandle(si.hStdInput);
    (void) CloseHandle(pi.hThread);

    return ((pid_tt) pi.hProcess);
}

static int
pipe(int *fds)
{
    return (_pipe(fds, BUFSIZ, _O_BINARY));
}
#endif /* !NO_CGI */

static int
set_non_blocking_mode(struct mg_connection *conn, SOCKET sock)
{
    unsigned long	on = 1;

    conn = NULL; /* unused */
    return (ioctlsocket(sock, FIONBIO, &on));
}

#else

static int
mg_stat(const char *path, struct mgstat *stp)
{
    struct stat	st;
    int		ok;

    if (stat(path, &st) == 0)
    {
        ok = 0;
        stp->size = st.st_size;
        stp->mtime = st.st_mtime;
        stp->is_directory = S_ISDIR(st.st_mode);
    }
    else
    {
        ok = -1;
    }

    return (ok);
}

static void
set_close_on_exec(int fd)
{
    (void) fcntl(fd, F_SETFD, FD_CLOEXEC);
}

static int
start_thread(struct mg_context *ctx, mg_thread_func_t func, void *param)
{
    pthread_t	thread_id;
    pthread_attr_t	attr;
    int		retval;

    (void) pthread_attr_init(&attr);
    (void) pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);

    if ((retval = pthread_create(&thread_id, &attr, func, param)) != 0)
        cry(fc(ctx), "%s: %s", __func__, strerror(retval));

    return (retval);
}

#ifndef NO_CGI
static pid_tt
spawn_process(struct mg_connection *conn, const char *prog, char *envblk,
              char *envp[], int fd_stdin, int fd_stdout, const char *dir)
{
    pid_tt		pid;
    const char	*interp;

    envblk = NULL;	/* unused */

    if ((pid = fork()) == -1)
    {
        /* Parent */
        send_error(conn, 500, http_500_error,
                   "fork(): %s", strerror(ERRNO));
    }
    else if (pid == 0)
    {
        /* Child */
        if (chdir(dir) != 0)
        {
            cry(conn, "%s: chdir(%s): %s",
                __func__, dir, strerror(ERRNO));
        }
        else if (dup2(fd_stdin, 0) == -1)
        {
            cry(conn, "%s: dup2(stdin, %d): %s",
                __func__, fd_stdin, strerror(ERRNO));
        }
        else if (dup2(fd_stdout, 1) == -1)
        {
            cry(conn, "%s: dup2(stdout, %d): %s",
                __func__, fd_stdout, strerror(ERRNO));
        }
        else
        {
            /* If error file is specified, send errors there */
            if (conn->ctx->error_log != NULL)
                (void) dup2(fileno(conn->ctx->error_log), 2);

            (void) close(fd_stdin);
            (void) close(fd_stdout);

            /* Execute CGI program */
            interp = conn->ctx->options[OPT_CGI_INTERPRETER];
            if (interp == NULL)
            {
                (void) execle(prog, prog, NULL, envp);
                cry(conn, "%s: execle(%s): %s",
                    __func__, prog, strerror(ERRNO));
            }
            else
            {
                (void) execle(interp, interp, prog, NULL, envp);
                cry(conn, "%s: execle(%s %s): %s",
                    __func__, interp, prog, strerror(ERRNO));
            }
        }
        exit(EXIT_FAILURE);
    }
    else
    {
        /* Parent. Close stdio descriptors */
        (void) close(fd_stdin);
        (void) close(fd_stdout);
    }

    return (pid);
}
#endif /* !NO_CGI */

static int
set_non_blocking_mode(struct mg_connection *conn, SOCKET sock)
{
    int	flags, ok = -1;

    if ((flags = fcntl(sock, F_GETFL, 0)) == -1)
    {
        cry(conn, "%s: fcntl(F_GETFL): %d", __func__, ERRNO);
    }
    else if (fcntl(sock, F_SETFL, flags | O_NONBLOCK) != 0)
    {
        cry(conn, "%s: fcntl(F_SETFL): %d", __func__, ERRNO);
    }
    else
    {
        ok = 0;	/* Success */
    }

    return (ok);
}
#endif /* _WIN32 */

static void
lock_option(struct mg_context *ctx, int opt_index)
{
    if (pthread_mutex_lock(&ctx->opt_mutex[opt_index]) != 0)
        cry(fc(ctx), "pthread_mutex_lock: %s", strerror(ERRNO));
}

static void
unlock_option(struct mg_context *ctx, int opt_index)
{
    if (pthread_mutex_unlock(&ctx->opt_mutex[opt_index]) != 0)
        cry(fc(ctx), "pthread_mutex_unlock: %s", strerror(ERRNO));
}

/*
 * Write data to the IO channel - opened file descriptor, socket or SSL
 * descriptor. Return number of bytes written.
 */

static uint64_t
push(FILE *fp, SOCKET sock, SSL *ssl, const char *buf, uint64_t len)
{
    uint64_t	sent;
    int		n, k;

    sent = 0;
    while (sent < len)
    {

        /* How many bytes we send in this iteration */
        k = len - sent > INT_MAX ? INT_MAX : (int) (len - sent);

        if (ssl != NULL)
        {
            n = SSL_write(ssl, buf + sent, k);
        }
        else if (fp != NULL)
        {
            n = fwrite(buf + sent, 1, k, fp);
            if (ferror(fp))
                n = -1;
        }
        else
        {
            n = send(sock, buf + sent, k, 0);
        }

        if (n < 0)
            break;

        sent += n;
    }

    return (sent);
}

static uint64_t
push_udt(FILE *fp, UDTSOCKET sock, SSL *ssl, const char *buf, uint64_t len)
{
    uint64_t	sent;
    int		n, k;

    printf("send resopone: %s, \n size: %d \n", buf, len);
    sent = 0;
    while (sent < len)
    {

        /* How many bytes we send in this iteration */
        k = len - sent > INT_MAX ? INT_MAX : (int) (len - sent);

        if (fp != NULL)
        {
            n = fwrite(buf + sent, 1, k, fp);
            if (ferror(fp))
                n = -1;
        }
        else
        {
            n = UDT::send(sock, buf + sent, k, 0);
        }

        if (n < 0)
            break;

        sent += n;
    }

    return (sent);
}
/*
 * Read from IO channel - opened file descriptor, socket, or SSL descriptor.
 * Return number of bytes read.
 */
static int
pull(FILE *fp, SOCKET sock, SSL *ssl, char *buf, int len)
{
    int	nread;

    if (ssl != NULL)
    {
        nread = SSL_read(ssl, buf, len);
    }
    else if (fp != NULL)
    {
        nread = fread(buf, 1, (size_t) len, fp);
        if (ferror(fp))
            nread = -1;
    }
    else
    {
        nread = recv(sock, buf, (size_t) len, 0);
    }

    return (nread);
}

static int
pull_udt(FILE *fp, UDTSOCKET sock, SSL *ssl, char *buf, int len)
{
    int	nread;
    if (fp != NULL)
    {
        nread = fread(buf, 1, (size_t) len, fp);
        if (ferror(fp))
            nread = -1;
    }
    else
    {
        nread = UDT::recv(sock, buf, (size_t) len, 0);
        printf("receive data: %s", buf);
    }

    return (nread);
}

int
mg_write(struct mg_connection *conn, const void *buf, int len)
{
    assert(len >= 0);
#ifdef _UDT_
    return ((int) push_udt(NULL, conn->client.sock, conn->ssl,
                           (const char *) buf, (uint64_t) len));
#else
    return ((int) push(NULL, conn->client.sock, conn->ssl,
                       (const char *) buf, (uint64_t) len));
#endif
}

int
mg_printf(struct mg_connection *conn, const char *fmt, ...)
{
    char	buf[MAX_REQUEST_SIZE];
    int	len;
    va_list	ap;

    va_start(ap, fmt);
    len = mg_vsnprintf(conn, buf, sizeof(buf), fmt, ap);
    va_end(ap);

    return (mg_write(conn, buf, len));
}

/*
 * Return content length of the request, or UNKNOWN_CONTENT_LENGTH constant if
 * Content-Length header is not set.
 */
static uint64_t
get_content_length(const struct mg_connection *conn)
{
    const char *cl = mg_get_header(conn, "Content-Length");
    return (cl == NULL ? UNKNOWN_CONTENT_LENGTH : strtoull(cl, NULL, 10));
}

/*
 * URL-decode input buffer into destination buffer.
 * 0-terminate the destination buffer. Return the length of decoded data.
 * form-url-encoded data differs from URI encoding in a way that it
 * uses '+' as character for space, see RFC 1866 section 8.2.1
 * http://ftp.ics.uci.edu/pub/ietf/html/rfc1866.txt
 */
static size_t
url_decode(const char *src, size_t src_len, char *dst, size_t dst_len,
           bool_t is_form_url_encoded)
{
    size_t	i, j;
    int	a, b;
#define	HEXTOI(x)	(isdigit(x) ? x - '0' : x - 'W')

    for (i = j = 0; i < src_len && j < dst_len - 1; i++, j++)
    {
        if (src[i] == '%' &&
                isxdigit(* (unsigned char *) (src + i + 1)) &&
                isxdigit(* (unsigned char *) (src + i + 2)))
        {
            a = tolower(* (unsigned char *) (src + i + 1));
            b = tolower(* (unsigned char *) (src + i + 2));
            dst[j] = ((HEXTOI(a) << 4) | HEXTOI(b)) & 0xff;
            i += 2;
        }
        else if (is_form_url_encoded && src[i] == '+')
        {
            dst[j] = ' ';
        }
        else
        {
            dst[j] = src[i];
        }
    }

    dst[j] = '\0';	/* Null-terminate the destination */

    return (j);
}

/*
 * Search for a form variable in a given buffer.
 * Semantic is the same as for mg_get_var().
 */
static char *
get_var(const char *name, const char *buf, size_t buf_len)
{
    const char	*p, *e, *s;
    char		*val;
    size_t		var_len, len;

    var_len = strlen(name);
    e = buf + buf_len;
    val = NULL;

    /* buf is "var1=val1&var2=val2...". Find variable first */
    for (p = buf; p + var_len < e; p++)
        if ((p == buf || p[-1] == '&') && p[var_len] == '=' &&
                !mg_strncasecmp(name, p, var_len))
        {

            /* Point p to variable value */
            p += var_len + 1;

            /* Point s to the end of the value */
            s = (const char *) memchr(p, '&', e - p);
            if (s == NULL)
                s = e;

            /* Try to allocate the buffer */
            len = s - p;
            if ((val = (char *) malloc(len + 1)) != NULL)
                (void) url_decode(p, len, val, len + 1, TRUE);
            break;
        }

    return (val);
}

/*
 * Free the pointer returned by mg_get_var(). This is needed for languages
 * like python, to have an ability to free allocated data without
 * loading C runtime library and calling free().
 */
void
mg_free(char *data)
{
    free(data);
}

/*
 * Return form data variable.
 * It can be specified in query string, or in the POST data.
 * Return NULL if the variable not found, or allocated 0-terminated value.
 * It is caller's responsibility to free the returned value.
 */
char *
mg_get_var(const struct mg_connection *conn, const char *name)
{
    const struct mg_request_info	*ri = &conn->request_info;
    char				*v1, *v2;

    v1 = v2 = NULL;

    /* Look in both query_string and POST data */
    if (ri->query_string != NULL)
        v1 = get_var(name, ri->query_string, strlen(ri->query_string));
    if (ri->post_data_len > 0)
        v2 = get_var(name, ri->post_data, ri->post_data_len);

    /* If they both have queried variable, POST data wins */
    if (v1 != NULL && v2 != NULL)
        free(v1);

    return (v2 == NULL ? v1 : v2);
}

/*
 * Transform URI to the file name.
 */
static void
convert_uri_to_file_name(struct mg_connection *conn, const char *uri,
                         char *buf, size_t buf_len)
{
    struct mg_context	*ctx = conn->ctx;
    struct vec		uri_vec, path_vec;
    const char		*list;

    lock_option(ctx, OPT_ROOT);
    mg_snprintf(conn, buf, buf_len, "%s%s", ctx->options[OPT_ROOT], uri);
    unlock_option(ctx, OPT_ROOT);

    /* If requested URI has aliased prefix, use alternate root */
    lock_option(ctx, OPT_ALIASES);
    list = ctx->options[OPT_ALIASES];

    while ((list = next_option(list, &uri_vec, &path_vec)) != NULL)
    {
        if (memcmp(uri, uri_vec.ptr, uri_vec.len) == 0)
        {
            (void) mg_snprintf(conn, buf, buf_len, "%.*s%s",
                               path_vec.len, path_vec.ptr, uri + uri_vec.len);
            break;
        }
    }
    unlock_option(ctx, OPT_ALIASES);

#ifdef _WIN32
    fix_directory_separators(buf);
#endif /* _WIN32 */
}

/*
 * Setup listening socket on given address, return socket.
 * Address format: [local_ip_address:]port_number
 */
static SOCKET
mg_open_listening_port(struct mg_context *ctx, const char *str, struct usa *usa)
{
    SOCKET		sock;
    int		on = 1, a, b, c, d, port;

    /* MacOS needs that. If we do not zero it, bind() will fail. */
    (void) memset(usa, 0, sizeof(*usa));

    if (sscanf(str, "%d.%d.%d.%d:%d", &a, &b, &c, &d, &port) == 5)
    {
        /* IP address to bind to is specified */
        usa->u.sin.sin_addr.s_addr =
            htonl((a << 24) | (b << 16) | (c << 8) | d);
    }
    else if (sscanf(str, "%d", &port) == 1)
    {
        /* Only port number is specified. Bind to all addresses */
        usa->u.sin.sin_addr.s_addr = htonl(INADDR_ANY);
    }
    else
    {
        return (INVALID_SOCKET);
    }

    usa->len			= sizeof(usa->u.sin);
    usa->u.sin.sin_family		= AF_INET;
    usa->u.sin.sin_port		= htons((uint16_t) port);

    if ((sock = socket(PF_INET, SOCK_STREAM, 6)) != INVALID_SOCKET &&
            setsockopt(sock, SOL_SOCKET, SO_REUSEADDR,
                       (char *) &on, sizeof(on)) == 0 &&
            bind(sock, &usa->u.sa, usa->len) == 0 &&
            listen(sock, 128) == 0)
    {
        /* Success */
        set_close_on_exec(sock);
    }
    else
    {
        /* Error */
        cry(fc(ctx), "%s(%d): %s", __func__, port, strerror(ERRNO));
        if (sock != INVALID_SOCKET)
            (void) closesocket(sock);
        sock = INVALID_SOCKET;
    }

    return (sock);
}

static UDTSOCKET
mg_open_listening_port_udt(struct mg_context *ctx, const char *str, struct usa *usa)
{
    UDTSOCKET		sock;
    int		on = 1, a, b, c, d, port;

    /* MacOS needs that. If we do not zero it, bind() will fail. */
    (void) memset(usa, 0, sizeof(*usa));

    if (sscanf(str, "%d.%d.%d.%d:%d", &a, &b, &c, &d, &port) == 5)
    {
        /* IP address to bind to is specified */
        usa->u.sin.sin_addr.s_addr =
            htonl((a << 24) | (b << 16) | (c << 8) | d);
    }
    else if (sscanf(str, "%d", &port) == 1)
    {
        /* Only port number is specified. Bind to all addresses */
        usa->u.sin.sin_addr.s_addr = htonl(INADDR_ANY);
    }
    else
    {
        return (INVALID_SOCKET);
    }

    usa->len			= sizeof(usa->u.sin);
    usa->u.sin.sin_family		= AF_INET;
    usa->u.sin.sin_port		= htons((uint16_t) port);

    if ((sock = UDT::socket(AF_INET, SOCK_STREAM, 0)) != INVALID_SOCKET &&
            UDT::bind(sock, &usa->u.sa, usa->len) == 0 &&
            UDT::listen(sock, 128) == 0)
    {
        /* Success */
        set_close_on_exec(sock);
    }
    else
    {
        /* Error */
        cry(fc(ctx), "%s(%d): %s", __func__, port, strerror(ERRNO));
        if (sock != INVALID_SOCKET)
            (void) closesocket(sock);
        sock = INVALID_SOCKET;
    }

    return (sock);
}
/*
 * Check whether full request is buffered. Return:
 *   -1         if request is malformed
 *    0         if request is not yet fully buffered
 *   >0         actual request length, including last \r\n\r\n
 */
static int
get_request_len(const char *buf, size_t buflen)
{
    const char	*s, *e;
    int		len = 0;

    for (s = buf, e = s + buflen - 1; len <= 0 && s < e; s++)
        /* Control characters are not allowed but >=128 is. */
        if (!isprint(* (unsigned char *) s) && *s != '\r' &&
                *s != '\n' && * (unsigned char *) s < 128)
            len = -1;
        else if (s[0] == '\n' && s[1] == '\n')
            len = (int) (s - buf) + 2;
        else if (s[0] == '\n' && &s[1] < e &&
                 s[1] == '\r' && s[2] == '\n')
            len = (int) (s - buf) + 3;

    return (len);
}

/*
 * Convert month to the month number. Return -1 on error, or month number
 */
static int
montoi(const char *s)
{
    size_t	i;

    for (i = 0; i < sizeof(month_names) / sizeof(month_names[0]); i++)
        if (!strcmp(s, month_names[i]))
            return ((int) i);

    return (-1);
}

/*
 * Parse date-time string, and return the corresponding time_t value
 */
static time_t
date_to_epoch(const char *s)
{
    time_t		current_time;
    struct tm	tm, *tmp;
    char		mon[32];
    int		sec, min, hour, mday, month, year;

    (void) memset(&tm, 0, sizeof(tm));
    sec = min = hour = mday = month = year = 0;

    if (((sscanf(s, "%d/%3s/%d %d:%d:%d",
                 &mday, mon, &year, &hour, &min, &sec) == 6) ||
            (sscanf(s, "%d %3s %d %d:%d:%d",
                    &mday, mon, &year, &hour, &min, &sec) == 6) ||
            (sscanf(s, "%*3s, %d %3s %d %d:%d:%d",
                    &mday, mon, &year, &hour, &min, &sec) == 6) ||
            (sscanf(s, "%d-%3s-%d %d:%d:%d",
                    &mday, mon, &year, &hour, &min, &sec) == 6)) &&
            (month = montoi(mon)) != -1)
    {
        tm.tm_mday	= mday;
        tm.tm_mon	= month;
        tm.tm_year	= year;
        tm.tm_hour	= hour;
        tm.tm_min	= min;
        tm.tm_sec	= sec;
    }

    if (tm.tm_year > 1900)
        tm.tm_year -= 1900;
    else if (tm.tm_year < 70)
        tm.tm_year += 100;

    /* Set Daylight Saving Time field */
    current_time = time(NULL);
    tmp = localtime(&current_time);
    tm.tm_isdst = tmp->tm_isdst;

    return (mktime(&tm));
}

/*
 * Protect against directory disclosure attack by removing '..',
 * excessive '/' and '\' characters
 */
static void
remove_double_dots_and_double_slashes(char *s)
{
    char	*p = s;

    while (*s != '\0')
    {
        *p++ = *s++;
        if (s[-1] == '/' || s[-1] == '\\')
        {
            /* Skip all following slashes and backslashes */
            while (*s == '/' || *s == '\\')
                s++;

            /* Skip all double-dots */
            while (*s == '.' && s[1] == '.')
                s += 2;
        }
    }
    *p = '\0';
}

/*
 * Built-in mime types
 */
static const struct
{
    const char	*extension;
    size_t		ext_len;
    const char	*mime_type;
    size_t		mime_type_len;
} mime_types[] =
{
    {".html",	5,	"text/html",			9},
    {".htm",	4,	"text/html",			9},
    {".shtm",	5,	"text/html",			9},
    {".shtml",	6,	"text/html",			9},
    {".css",	4,	"text/css",			8},
    {".js",		3,	"application/x-javascript",	24},
    {".ico",	4,	"image/x-icon",			12},
    {".gif",	4,	"image/gif",			9},
    {".jpg",	4,	"image/jpeg",			10},
    {".jpeg",	5,	"image/jpeg",			10},
    {".png",	4,	"image/png",			9},
    {".svg",	4,	"image/svg+xml",		13},
    {".torrent",	8,	"application/x-bittorrent",	24},
    {".wav",	4,	"audio/x-wav",			11},
    {".mp3",	4,	"audio/x-mp3",			11},
    {".mid",	4,	"audio/mid",			9},
    {".m3u",	4,	"audio/x-mpegurl",		15},
    {".ram",	4,	"audio/x-pn-realaudio",		20},
    {".ra",		3,	"audio/x-pn-realaudio",		20},
    {".doc",	4,	"application/msword",		19},
    {".exe",	4,	"application/octet-stream",	24},
    {".zip",	4,	"application/x-zip-compressed",	28},
    {".xls",	4,	"application/excel",		17},
    {".tgz",	4,	"application/x-tar-gz",		20},
    {".tar",	4,	"application/x-tar",		17},
    {".gz",		3,	"application/x-gunzip",		20},
    {".arj",	4,	"application/x-arj-compressed",	28},
    {".rar",	4,	"application/x-arj-compressed",	28},
    {".rtf",	4,	"application/rtf",		15},
    {".pdf",	4,	"application/pdf",		15},
    {".swf",	4,	"application/x-shockwave-flash",29},
    {".mpg",	4,	"video/mpeg",			10},
    {".mpeg",	5,	"video/mpeg",			10},
    {".asf",	4,	"video/x-ms-asf",		14},
    {".avi",	4,	"video/x-msvideo",		15},
    {".bmp",	4,	"image/bmp",			9},
    {NULL,		0,	NULL,				0}
};

/*
 * Look at the "path" extension and figure what mime type it has.
 * Store mime type in the vector.
 */
static void
get_mime_type(struct mg_context *ctx, const char *path, struct vec *vec)
{
    struct vec	ext_vec, mime_vec;
    const char	*list, *ext;
    size_t		i, path_len;

    path_len = strlen(path);

    /*
     * Scan user-defined mime types first, in case user wants to
     * override default mime types.
     */
    lock_option(ctx, OPT_MIME_TYPES);
    list = ctx->options[OPT_MIME_TYPES];
    while ((list = next_option(list, &ext_vec, &mime_vec)) != NULL)
    {
        /* ext now points to the path suffix */
        ext = path + path_len - ext_vec.len;
        if (mg_strncasecmp(ext, ext_vec.ptr, ext_vec.len) == 0)
        {
            *vec = mime_vec;
            unlock_option(ctx, OPT_MIME_TYPES);
            return;
        }
    }
    unlock_option(ctx, OPT_MIME_TYPES);

    /* Now scan built-in mime types */
    for (i = 0; mime_types[i].extension != NULL; i++)
    {
        ext = path + (path_len - mime_types[i].ext_len);
        if (path_len > mime_types[i].ext_len &&
                mg_strcasecmp(ext, mime_types[i].extension) == 0)
        {
            vec->ptr = mime_types[i].mime_type;
            vec->len = mime_types[i].mime_type_len;
            return;
        }
    }

    /* Nothing found. Fall back to text/plain */
    vec->ptr = "text/plain";
    vec->len = 10;
}

#ifndef HAVE_MD5
typedef struct MD5Context
{
    uint32_t	buf[4];
    uint32_t	bits[2];
    unsigned char	in[64];
} MD5_CTX;

#if __BYTE_ORDER == 1234
#define byteReverse(buf, len)	/* Nothing */
#else
/*
* Note: this code is harmless on little-endian machines.
*/
static void
byteReverse(unsigned char *buf, unsigned longs)
{
    uint32_t t;
    do
    {
        t = (uint32_t) ((unsigned) buf[3] << 8 | buf[2]) << 16 |
            ((unsigned) buf[1] << 8 | buf[0]);
        *(uint32_t *) buf = t;
        buf += 4;
    }
    while (--longs);
}
#endif /* __BYTE_ORDER */

/* The four core functions - F1 is optimized somewhat */

/* #define F1(x, y, z) (x & y | ~x & z) */
#define F1(x, y, z) (z ^ (x & (y ^ z)))
#define F2(x, y, z) F1(z, x, y)
#define F3(x, y, z) (x ^ y ^ z)
#define F4(x, y, z) (y ^ (x | ~z))

/* This is the central step in the MD5 algorithm. */
#define MD5STEP(f, w, x, y, z, data, s) \
( w += f(x, y, z) + data,  w = w<<s | w>>(32-s),  w += x )

/*
 * Start MD5 accumulation.  Set bit count to 0 and buffer to mysterious
 * initialization constants.
 */
static void
MD5Init(MD5_CTX *ctx)
{
    ctx->buf[0] = 0x67452301;
    ctx->buf[1] = 0xefcdab89;
    ctx->buf[2] = 0x98badcfe;
    ctx->buf[3] = 0x10325476;

    ctx->bits[0] = 0;
    ctx->bits[1] = 0;
}

/*
 * The core of the MD5 algorithm, this alters an existing MD5 hash to
 * reflect the addition of 16 longwords of new data.  MD5Update blocks
 * the data and converts bytes into longwords for this routine.
 */
static void
MD5Transform(uint32_t buf[4], uint32_t const in[16])
{
    register uint32_t a, b, c, d;

    a = buf[0];
    b = buf[1];
    c = buf[2];
    d = buf[3];

    MD5STEP(F1, a, b, c, d, in[0] + 0xd76aa478, 7);
    MD5STEP(F1, d, a, b, c, in[1] + 0xe8c7b756, 12);
    MD5STEP(F1, c, d, a, b, in[2] + 0x242070db, 17);
    MD5STEP(F1, b, c, d, a, in[3] + 0xc1bdceee, 22);
    MD5STEP(F1, a, b, c, d, in[4] + 0xf57c0faf, 7);
    MD5STEP(F1, d, a, b, c, in[5] + 0x4787c62a, 12);
    MD5STEP(F1, c, d, a, b, in[6] + 0xa8304613, 17);
    MD5STEP(F1, b, c, d, a, in[7] + 0xfd469501, 22);
    MD5STEP(F1, a, b, c, d, in[8] + 0x698098d8, 7);
    MD5STEP(F1, d, a, b, c, in[9] + 0x8b44f7af, 12);
    MD5STEP(F1, c, d, a, b, in[10] + 0xffff5bb1, 17);
    MD5STEP(F1, b, c, d, a, in[11] + 0x895cd7be, 22);
    MD5STEP(F1, a, b, c, d, in[12] + 0x6b901122, 7);
    MD5STEP(F1, d, a, b, c, in[13] + 0xfd987193, 12);
    MD5STEP(F1, c, d, a, b, in[14] + 0xa679438e, 17);
    MD5STEP(F1, b, c, d, a, in[15] + 0x49b40821, 22);

    MD5STEP(F2, a, b, c, d, in[1] + 0xf61e2562, 5);
    MD5STEP(F2, d, a, b, c, in[6] + 0xc040b340, 9);
    MD5STEP(F2, c, d, a, b, in[11] + 0x265e5a51, 14);
    MD5STEP(F2, b, c, d, a, in[0] + 0xe9b6c7aa, 20);
    MD5STEP(F2, a, b, c, d, in[5] + 0xd62f105d, 5);
    MD5STEP(F2, d, a, b, c, in[10] + 0x02441453, 9);
    MD5STEP(F2, c, d, a, b, in[15] + 0xd8a1e681, 14);
    MD5STEP(F2, b, c, d, a, in[4] + 0xe7d3fbc8, 20);
    MD5STEP(F2, a, b, c, d, in[9] + 0x21e1cde6, 5);
    MD5STEP(F2, d, a, b, c, in[14] + 0xc33707d6, 9);
    MD5STEP(F2, c, d, a, b, in[3] + 0xf4d50d87, 14);
    MD5STEP(F2, b, c, d, a, in[8] + 0x455a14ed, 20);
    MD5STEP(F2, a, b, c, d, in[13] + 0xa9e3e905, 5);
    MD5STEP(F2, d, a, b, c, in[2] + 0xfcefa3f8, 9);
    MD5STEP(F2, c, d, a, b, in[7] + 0x676f02d9, 14);
    MD5STEP(F2, b, c, d, a, in[12] + 0x8d2a4c8a, 20);

    MD5STEP(F3, a, b, c, d, in[5] + 0xfffa3942, 4);
    MD5STEP(F3, d, a, b, c, in[8] + 0x8771f681, 11);
    MD5STEP(F3, c, d, a, b, in[11] + 0x6d9d6122, 16);
    MD5STEP(F3, b, c, d, a, in[14] + 0xfde5380c, 23);
    MD5STEP(F3, a, b, c, d, in[1] + 0xa4beea44, 4);
    MD5STEP(F3, d, a, b, c, in[4] + 0x4bdecfa9, 11);
    MD5STEP(F3, c, d, a, b, in[7] + 0xf6bb4b60, 16);
    MD5STEP(F3, b, c, d, a, in[10] + 0xbebfbc70, 23);
    MD5STEP(F3, a, b, c, d, in[13] + 0x289b7ec6, 4);
    MD5STEP(F3, d, a, b, c, in[0] + 0xeaa127fa, 11);
    MD5STEP(F3, c, d, a, b, in[3] + 0xd4ef3085, 16);
    MD5STEP(F3, b, c, d, a, in[6] + 0x04881d05, 23);
    MD5STEP(F3, a, b, c, d, in[9] + 0xd9d4d039, 4);
    MD5STEP(F3, d, a, b, c, in[12] + 0xe6db99e5, 11);
    MD5STEP(F3, c, d, a, b, in[15] + 0x1fa27cf8, 16);
    MD5STEP(F3, b, c, d, a, in[2] + 0xc4ac5665, 23);

    MD5STEP(F4, a, b, c, d, in[0] + 0xf4292244, 6);
    MD5STEP(F4, d, a, b, c, in[7] + 0x432aff97, 10);
    MD5STEP(F4, c, d, a, b, in[14] + 0xab9423a7, 15);
    MD5STEP(F4, b, c, d, a, in[5] + 0xfc93a039, 21);
    MD5STEP(F4, a, b, c, d, in[12] + 0x655b59c3, 6);
    MD5STEP(F4, d, a, b, c, in[3] + 0x8f0ccc92, 10);
    MD5STEP(F4, c, d, a, b, in[10] + 0xffeff47d, 15);
    MD5STEP(F4, b, c, d, a, in[1] + 0x85845dd1, 21);
    MD5STEP(F4, a, b, c, d, in[8] + 0x6fa87e4f, 6);
    MD5STEP(F4, d, a, b, c, in[15] + 0xfe2ce6e0, 10);
    MD5STEP(F4, c, d, a, b, in[6] + 0xa3014314, 15);
    MD5STEP(F4, b, c, d, a, in[13] + 0x4e0811a1, 21);
    MD5STEP(F4, a, b, c, d, in[4] + 0xf7537e82, 6);
    MD5STEP(F4, d, a, b, c, in[11] + 0xbd3af235, 10);
    MD5STEP(F4, c, d, a, b, in[2] + 0x2ad7d2bb, 15);
    MD5STEP(F4, b, c, d, a, in[9] + 0xeb86d391, 21);

    buf[0] += a;
    buf[1] += b;
    buf[2] += c;
    buf[3] += d;
}

/*
 * Update context to reflect the concatenation of another buffer full
 * of bytes.
 */
static void
MD5Update(MD5_CTX *ctx, unsigned char const *buf, unsigned len)
{
    uint32_t t;

    /* Update bitcount */

    t = ctx->bits[0];
    if ((ctx->bits[0] = t + ((uint32_t) len << 3)) < t)
        ctx->bits[1]++;		/* Carry from low to high */
    ctx->bits[1] += len >> 29;

    t = (t >> 3) & 0x3f;	/* Bytes already in shsInfo->data */

    /* Handle any leading odd-sized chunks */

    if (t)
    {
        unsigned char *p = (unsigned char *) ctx->in + t;

        t = 64 - t;
        if (len < t)
        {
            memcpy(p, buf, len);
            return;
        }
        memcpy(p, buf, t);
        byteReverse(ctx->in, 16);
        MD5Transform(ctx->buf, (uint32_t *) ctx->in);
        buf += t;
        len -= t;
    }
    /* Process data in 64-byte chunks */

    while (len >= 64)
    {
        memcpy(ctx->in, buf, 64);
        byteReverse(ctx->in, 16);
        MD5Transform(ctx->buf, (uint32_t *) ctx->in);
        buf += 64;
        len -= 64;
    }

    /* Handle any remaining bytes of data. */

    memcpy(ctx->in, buf, len);
}

/*
 * Final wrapup - pad to 64-byte boundary with the bit pattern
 * 1 0* (64-bit count of bits processed, MSB-first)
 */
static void
MD5Final(unsigned char digest[16], MD5_CTX *ctx)
{
    unsigned count;
    unsigned char *p;

    /* Compute number of bytes mod 64 */
    count = (ctx->bits[0] >> 3) & 0x3F;

    /* Set the first char of padding to 0x80.  This is safe since there is
       always at least one byte free */
    p = ctx->in + count;
    *p++ = 0x80;

    /* Bytes of padding needed to make 64 bytes */
    count = 64 - 1 - count;

    /* Pad out to 56 mod 64 */
    if (count < 8)
    {
        /* Two lots of padding:  Pad the first block to 64 bytes */
        memset(p, 0, count);
        byteReverse(ctx->in, 16);
        MD5Transform(ctx->buf, (uint32_t *) ctx->in);

        /* Now fill the next block with 56 bytes */
        memset(ctx->in, 0, 56);
    }
    else
    {
        /* Pad block to 56 bytes */
        memset(p, 0, count - 8);
    }
    byteReverse(ctx->in, 14);

    /* Append length in bits and transform */
    ((uint32_t *) ctx->in)[14] = ctx->bits[0];
    ((uint32_t *) ctx->in)[15] = ctx->bits[1];

    MD5Transform(ctx->buf, (uint32_t *) ctx->in);
    byteReverse((unsigned char *) ctx->buf, 4);
    memcpy(digest, ctx->buf, 16);
    memset((char *) ctx, 0, sizeof(ctx));	/* In case it's sensitive */
}
#endif /* !HAVE_MD5 */

/*
 * Stringify binary data. Output buffer must be twice as big as input,
 * because each byte takes 2 bytes in string representation
 */
static void
bin2str(char *to, const unsigned char *p, size_t len)
{
    static const char *hex = "0123456789abcdef";

    for (; len--; p++)
    {
        *to++ = hex[p[0] >> 4];
        *to++ = hex[p[0] & 0x0f];
    }
    *to = '\0';
}

/*
 * Return stringified MD5 hash for list of vectors.
 * buf must point to 33-bytes long buffer
 */
static void
mg_md5(char *buf, ...)
{
    unsigned char	hash[16];
    const char	*p;
    va_list		ap;
    MD5_CTX		ctx;

    MD5Init(&ctx);

    va_start(ap, buf);
    while ((p = va_arg(ap, const char *)) != NULL)
        MD5Update(&ctx, (unsigned char *) p, (int) strlen(p));
    va_end(ap);

    MD5Final(hash, &ctx);
    bin2str(buf, hash, sizeof(hash));
}

/*
 * Check the user's password, return 1 if OK
 */
static bool_t
check_password(const char *method, const char *ha1, const char *uri,
               const char *nonce, const char *nc, const char *cnonce,
               const char *qop, const char *response)
{
    char	ha2[32 + 1], expected_response[32 + 1];

    /* XXX  Due to a bug in MSIE, we do not compare the URI	 */
    /* Also, we do not check for authentication timeout */
    if (/*strcmp(dig->uri, c->ouri) != 0 || */
        strlen(response) != 32 /*||
	    now - strtoul(dig->nonce, NULL, 10) > 3600 */)
        return (FALSE);

    mg_md5(ha2, method, ":", uri, NULL);
    mg_md5(expected_response, ha1, ":", nonce, ":", nc,
           ":", cnonce, ":", qop, ":", ha2, NULL);

    return (!mg_strcasecmp(response, expected_response));
}

/*
 * Use the global passwords file, if specified by auth_gpass option,
 * or search for .htpasswd in the requested directory.
 */
static FILE *
open_auth_file(struct mg_connection *conn, const char *path)
{
    struct mg_context	*ctx = conn->ctx;
    char 			name[FILENAME_MAX];
    const char		*p, *e;
    struct mgstat		st;
    FILE			*fp;

    if (ctx->options[OPT_AUTH_GPASSWD] != NULL)
    {
        /* Use global passwords file */
        fp =  mg_fopen(ctx->options[OPT_AUTH_GPASSWD], "r");
        if (fp == NULL)
            cry(fc(ctx), "fopen(%s): %s",
                ctx->options[OPT_AUTH_GPASSWD], strerror(ERRNO));
    }
    else if (!mg_stat(path, &st) && st.is_directory)
    {
        (void) mg_snprintf(conn, name, sizeof(name), "%s%c%s",
                           path, DIRSEP, PASSWORDS_FILE_NAME);
        fp = mg_fopen(name, "r");
    }
    else
    {
        /*
         * Try to find .htpasswd in requested directory.
         * Given the path, create the path to .htpasswd file
         * in the same directory. Find the right-most
         * directory separator character first. That would be the
         * directory name. If directory separator character is not
         * found, 'e' will point to 'p'.
         */
        for (p = path, e = p + strlen(p) - 1; e > p; e--)
            if (IS_DIRSEP_CHAR(*e))
                break;

        /*
         * Make up the path by concatenating directory name and
         * .htpasswd file name.
         */
        (void) mg_snprintf(conn, name, sizeof(name), "%.*s%c%s",
                           (int) (e - p), p, DIRSEP, PASSWORDS_FILE_NAME);
        fp = mg_fopen(name, "r");
    }

    return (fp);
}

/*
 * Parsed Authorization: header
 */
struct ah
{
    char	*user, *uri, *cnonce, *response, *qop, *nc, *nonce;
};

static bool_t
parse_auth_header(struct mg_connection *conn, char *buf, size_t buf_size,
                  struct ah *ah)
{
    char		*name, *value, *s;
    const char	*auth_header;

    if ((auth_header = mg_get_header(conn, "Authorization")) == NULL ||
            mg_strncasecmp(auth_header, "Digest ", 7) != 0)
        return (FALSE);

    /* Make modifiable copy of the auth header */
    (void) mg_strlcpy(buf, auth_header + 7, buf_size);

    s = buf;
    (void) memset(ah, 0, sizeof(*ah));

    /* Gobble initial spaces */
    while (isspace(* (unsigned char *) s))
        s++;

    /* Parse authorization header */
    for (;;)
    {
        name = skip(&s, "=");
        value = skip(&s, ", ");

        if (*value == '"')
        {
            value++;
            value[strlen(value) - 1] = '\0';
        }
        else if (*value == '\0')
        {
            break;
        }

        if (!strcmp(name, "username"))
        {
            ah->user = value;
        }
        else if (!strcmp(name, "cnonce"))
        {
            ah->cnonce = value;
        }
        else if (!strcmp(name, "response"))
        {
            ah->response = value;
        }
        else if (!strcmp(name, "uri"))
        {
            ah->uri = value;
        }
        else if (!strcmp(name, "qop"))
        {
            ah->qop = value;
        }
        else if (!strcmp(name, "nc"))
        {
            ah->nc = value;
        }
        else if (!strcmp(name, "nonce"))
        {
            ah->nonce = value;
        }
    }

    /* CGI needs it as REMOTE_USER */
    if (ah->user != NULL)
        conn->request_info.remote_user = mg_strdup(ah->user);

    return (TRUE);
}

/*
 * Authorize against the opened passwords file. Return 1 if authorized.
 */
static bool_t
authorize(struct mg_connection *conn, FILE *fp)
{
    struct ah	ah;
    char		line[256], f_user[256], domain[256], ha1[256],
    buf[MAX_REQUEST_SIZE];

    if (!parse_auth_header(conn, buf, sizeof(buf), &ah))
        return (FALSE);

    /* Loop over passwords file */
    while (fgets(line, sizeof(line), fp) != NULL)
    {

        if (sscanf(line, "%[^:]:%[^:]:%s", f_user, domain, ha1) != 3)
            continue;

        if (!strcmp(ah.user, f_user) &&
                !strcmp(domain, conn->ctx->options[OPT_AUTH_DOMAIN]))
            return (check_password(
                        conn->request_info.request_method, ha1,
                        ah.uri, ah.nonce, ah.nc, ah.cnonce,
                        ah.qop, ah.response));
    }

    return (FALSE);
}

/*
 * Return TRUE if request is authorised, FALSE otherwise.
 */
static bool_t
check_authorization(struct mg_connection *conn, const char *path)
{
    FILE		*fp;
    char		fname[FILENAME_MAX];
    struct vec	uri_vec, filename_vec;
    const char	*list;
    bool_t		authorized;

    fp = NULL;
    authorized = TRUE;

    lock_option(conn->ctx, OPT_PROTECT);
    list = conn->ctx->options[OPT_PROTECT];
    while ((list = next_option(list, &uri_vec, &filename_vec)) != NULL)
    {
        if (!memcmp(conn->request_info.uri, uri_vec.ptr, uri_vec.len))
        {
            (void) mg_snprintf(conn, fname, sizeof(fname), "%.*s",
                               filename_vec.len, filename_vec.ptr);
            if ((fp = mg_fopen(fname, "r")) == NULL)
                cry(conn, "%s: cannot open %s: %s",
                    __func__, fname, strerror(errno));
            break;
        }
    }
    unlock_option(conn->ctx, OPT_PROTECT);

    if (fp == NULL)
        fp = open_auth_file(conn, path);

    if (fp != NULL)
    {
        authorized = authorize(conn, fp);
        (void) fclose(fp);
    }

    return (authorized);
}

static void
send_authorization_request(struct mg_connection *conn)
{
    conn->request_info.status_code = 401;
    (void) mg_printf(conn,
                     "HTTP/1.1 401 Unauthorized\r\n"
                     "WWW-Authenticate: Digest qop=\"auth\", "
                     "realm=\"%s\", nonce=\"%lu\"\r\n\r\n",
                     conn->ctx->options[OPT_AUTH_DOMAIN], (unsigned long) time(NULL));
}

static bool_t
is_authorized_for_put(struct mg_connection *conn)
{
    FILE	*fp;
    int	ret = FALSE;

    if ((fp = mg_fopen(conn->ctx->options[OPT_AUTH_PUT], "r")) != NULL)
    {
        set_close_on_exec(fileno(fp));
        ret = authorize(conn, fp);
        (void) fclose(fp);
    }

    return (ret);
}

int
mg_modify_passwords_file(struct mg_context *ctx, const char *fname,
                         const char *user, const char *pass)
{
    int		found;
    char		line[512], u[512], d[512], ha1[33], tmp[FILENAME_MAX];
    const char	*domain;
    FILE		*fp, *fp2;

    found = 0;
    fp = fp2 = NULL;
    domain = ctx->options[OPT_AUTH_DOMAIN];

    /* Regard empty password as no password - remove user record. */
    if (pass[0] == '\0')
        pass = NULL;

    (void) snprintf(tmp, sizeof(tmp), "%s.tmp", fname);

    /* Create the file if does not exist */
    if ((fp = mg_fopen(fname, "a+")) != NULL)
        (void) fclose(fp);

    /* Open the given file and temporary file */
    if ((fp = mg_fopen(fname, "r")) == NULL)
    {
        cry(fc(ctx), "Cannot open %s: %s", fname, strerror(errno));
        return (0);
    }
    else if ((fp2 = mg_fopen(tmp, "w+")) == NULL)
    {
        cry(fc(ctx), "Cannot open %s: %s", tmp, strerror(errno));
        return (0);
    }

    /* Copy the stuff to temporary file */
    while (fgets(line, sizeof(line), fp) != NULL)
    {

        if (sscanf(line, "%[^:]:%[^:]:%*s", u, d) != 2)
            continue;

        if (!strcmp(u, user) && !strcmp(d, domain))
        {
            found++;
            if (pass != NULL)
            {
                mg_md5(ha1, user, ":", domain, ":", pass, NULL);
                fprintf(fp2, "%s:%s:%s\n", user, domain, ha1);
            }
        }
        else
        {
            (void) fprintf(fp2, "%s", line);
        }
    }

    /* If new user, just add it */
    if (!found && pass != NULL)
    {
        mg_md5(ha1, user, ":", domain, ":", pass, NULL);
        (void) fprintf(fp2, "%s:%s:%s\n", user, domain, ha1);
    }

    /* Close files */
    (void) fclose(fp);
    (void) fclose(fp2);

    /* Put the temp file in place of real file */
    (void) mg_remove(fname);
    (void) mg_rename(tmp, fname);

    return (0);
}

struct de
{
    struct mg_connection	*conn;
    char			*file_name;
    struct mgstat		st;
};

/*
 * This function is called from send_directory() and prints out
 * single directory entry.
 */
static void
print_dir_entry(struct de *de)
{
    char		size[64], mod[64];

    if (de->st.is_directory)
    {
        (void) mg_snprintf(de->conn,
                           size, sizeof(size), "%s", "[DIRECTORY]");
    }
    else
    {
        /*
         * We use (signed) cast below because MSVC 6 compiler cannot
         * convert unsigned __int64 to double. Sigh.
         */
        if (de->st.size < 1024)
            (void) mg_snprintf(de->conn, size, sizeof(size),
                               "%lu", (unsigned long) de->st.size);
        else if (de->st.size < 1024 * 1024)
            (void) mg_snprintf(de->conn, size, sizeof(size),
                               "%.1fk", (double) de->st.size / 1024.0);
        else if (de->st.size < 1024 * 1024 * 1024)
            (void) mg_snprintf(de->conn, size, sizeof(size),
                               "%.1fM", (double) de->st.size / 1048576);
        else
            (void) mg_snprintf(de->conn, size, sizeof(size),
                               "%.1fG", (double) de->st.size / 1073741824);
    }
    (void) strftime(mod, sizeof(mod), "%d-%b-%Y %H:%M",
                    localtime(&de->st.mtime));
    de->conn->num_bytes_sent += mg_printf(de->conn,
                                          "<tr><td><a href=\"%s%s\">%s%s</a></td>"
                                          "<td>&nbsp;%s</td><td>&nbsp;&nbsp;%s</td></tr>\n",
                                          de->conn->request_info.uri, de->file_name, de->file_name,
                                          de->st.is_directory ? "/" : "", mod, size);
}

/*
 * This function is called from send_directory() and used for
 * sorting direcotory entries by size, or name, or modification time.
 */
static int
compare_dir_entries(const void *p1, const void *p2)
{
    const struct de	*a = (struct de *) p1, *b = (struct de *) p2;
    const char	*query_string = a->conn->request_info.query_string;
    int		cmp_result = 0;

    if (query_string == NULL)
        query_string = "na";

    if (a->st.is_directory && !b->st.is_directory)
    {
        return (-1);  /* Always put directories on top */
    }
    else if (!a->st.is_directory && b->st.is_directory)
    {
        return (1);   /* Always put directories on top */
    }
    else if (*query_string == 'n')
    {
        cmp_result = strcmp(a->file_name, b->file_name);
    }
    else if (*query_string == 's')
    {
        cmp_result = a->st.size == b->st.size ? 0 :
                     a->st.size > b->st.size ? 1 : -1;
    }
    else if (*query_string == 'd')
    {
        cmp_result = a->st.mtime == b->st.mtime ? 0 :
                     a->st.mtime > b->st.mtime ? 1 : -1;
    }

    return (query_string[1] == 'd' ? -cmp_result : cmp_result);
}

/*
 * Send directory contents.
 */
static void
send_directory(struct mg_connection *conn, const char *dir)
{
    struct dirent	*dp;
    DIR		*dirp;
    struct de	*entries = NULL;
    char		path[FILENAME_MAX];
    int		i, sort_direction, num_entries = 0, arr_size = 128;

    if ((dirp = opendir(dir)) == NULL)
    {
        send_error(conn, 500, "Cannot open directory",
                   "Error: opendir(%s): %s", path, strerror(ERRNO));
        return;
    }

    (void) mg_printf(conn, "%s",
                     "HTTP/1.1 200 OK\r\n"
                     "Connection: close\r\n"
                     "Content-Type: text/html; charset=utf-8\r\n\r\n");

    sort_direction = conn->request_info.query_string != NULL &&
                     conn->request_info.query_string[1] == 'd' ? 'a' : 'd';

    while ((dp = readdir(dirp)) != NULL)
    {

        /* Do not show current dir and passwords file */
        if (!strcmp(dp->d_name, ".") ||
                !strcmp(dp->d_name, "..") ||
                !strcmp(dp->d_name, PASSWORDS_FILE_NAME))
            continue;

        if (entries == NULL || num_entries >= arr_size)
        {
            arr_size *= 2;
            entries = (struct de *) realloc(entries,
                                            arr_size * sizeof(entries[0]));
        }

        if (entries == NULL)
        {
            send_error(conn, 500, "Cannot open directory",
                       "%s", "Error: cannot allocate memory");
            return;
        }

        (void) mg_snprintf(conn, path, sizeof(path), "%s%c%s",
                           dir, DIRSEP, dp->d_name);

        (void) mg_stat(path, &entries[num_entries].st);
        entries[num_entries].conn = conn;
        entries[num_entries].file_name = mg_strdup(dp->d_name);
        num_entries++;
    }
    (void) closedir(dirp);

    conn->num_bytes_sent += mg_printf(conn,
                                      "<html><head><title>Index of %s</title>"
                                      "<style>th {text-align: left;}</style></head>"
                                      "<body><h1>Index of %s</h1><pre><table cellpadding=\"0\">"
                                      "<tr><th><a href=\"?n%c\">Name</a></th>"
                                      "<th><a href=\"?d%c\">Modified</a></th>"
                                      "<th><a href=\"?s%c\">Size</a></th></tr>"
                                      "<tr><td colspan=\"3\"><hr></td></tr>",
                                      conn->request_info.uri, conn->request_info.uri,
                                      sort_direction, sort_direction, sort_direction);

    /* Print first entry - link to a parent directory */
    conn->num_bytes_sent += mg_printf(conn,
                                      "<tr><td><a href=\"%s%s\">%s</a></td>"
                                      "<td>&nbsp;%s</td><td>&nbsp;&nbsp;%s</td></tr>\n",
                                      conn->request_info.uri, "..", "Parent directory", "-", "-");

    /* Sort and print directory entries */
    qsort(entries, num_entries, sizeof(entries[0]), compare_dir_entries);
    for (i = 0; i < num_entries; i++)
    {
        print_dir_entry(&entries[i]);
        free(entries[i].file_name);
    }
    free(entries);

    conn->num_bytes_sent += mg_printf(conn, "%s", "</table></body></html>");
    conn->request_info.status_code = 200;
}

/*
 * Send len bytes from the opened file to the client.
 */
static void
send_opened_file_stream(struct mg_connection *conn, FILE *fp, uint64_t len)
{
    char	buf[BUFSIZ];
    int	to_read, num_read, num_written;

    while (len > 0)
    {
        /* Calculate how much to read from the file in the buffer */
        to_read = sizeof(buf);
        if ((uint64_t) to_read > len)
            to_read = (int) len;

        /* Read from file, exit the loop on error */
        if ((num_read = fread(buf, 1, to_read, fp)) == 0)
            break;

        /* Send read bytes to the client, exit the loop on error */
        if ((num_written = mg_write(conn, buf, num_read)) != num_read)
            break;

        /* Both read and were successful, adjust counters */
        conn->num_bytes_sent += num_written;
        len -= num_written;
    }
}

/*
 * Send regular file contents.
 */
static void
send_file(struct mg_connection *conn, const char *path, struct mgstat *stp)
{
    char		date[64], lm[64], etag[64], range[64];
    const char	*fmt = "%a, %d %b %Y %H:%M:%S %Z", *msg = "OK", *hdr;
    time_t		curtime = time(NULL);
    uint64_t	cl, r1, r2;
    struct vec	mime_vec;
    FILE		*fp;
    int		n;

    get_mime_type(conn->ctx, path, &mime_vec);
    cl = stp->size;
    conn->request_info.status_code = 200;
    range[0] = '\0';

    if ((fp = mg_fopen(path, "rb")) == NULL)
    {
        send_error(conn, 500, http_500_error,
                   "fopen(%s): %s", path, strerror(ERRNO));
        return;
    }
    set_close_on_exec(fileno(fp));

    /* If Range: header specified, act accordingly */
    r1 = r2 = 0;
    hdr = mg_get_header(conn, "Range");
    if (hdr != NULL && (n = sscanf(hdr,
                                   "bytes=%" UINT64_FMT "u-%" UINT64_FMT "u", &r1, &r2)) > 0)
    {
        conn->request_info.status_code = 206;
        (void) fseeko(fp, (off_t) r1, SEEK_SET);
        cl = n == 2 ? r2 - r1 + 1: cl - r1;
        (void) mg_snprintf(conn, range, sizeof(range),
                           "Content-Range: bytes "
                           "%" UINT64_FMT "u-%"
                           UINT64_FMT "u/%" UINT64_FMT "u\r\n",
                           r1, r1 + cl - 1, stp->size);
        msg = "Partial Content";
    }

    /* Prepare Etag, Date, Last-Modified headers */
    (void) strftime(date, sizeof(date), fmt, localtime(&curtime));
    (void) strftime(lm, sizeof(lm), fmt, localtime(&stp->mtime));
    (void) mg_snprintf(conn, etag, sizeof(etag), "%lx.%lx",
                       (unsigned long) stp->mtime, (unsigned long) stp->size);

    (void) mg_printf(conn,
                     "HTTP/1.1 %d %s\r\n"
                     "Date: %s\r\n"
                     "Last-Modified: %s\r\n"
                     "Etag: \"%s\"\r\n"
                     "Content-Type: %.*s\r\n"
                     "Content-Length: %" UINT64_FMT "u\r\n"
                     "Connection: close\r\n"
                     "Accept-Ranges: bytes\r\n"
                     "%s\r\n",
                     conn->request_info.status_code, msg, date, lm, etag,
                     mime_vec.len, mime_vec.ptr, cl, range);

    if (strcmp(conn->request_info.request_method, "HEAD") != 0)
        send_opened_file_stream(conn, fp, cl);
    (void) fclose(fp);
}

/*
 * Parse HTTP headers from the given buffer, advance buffer to the point
 * where parsing stopped.
 */
static void
parse_http_headers(char **buf, struct mg_request_info *ri)
{
    int	i;

    for (i = 0; i < (int) ARRAY_SIZE(ri->http_headers); i++)
    {
        ri->http_headers[i].name = skip(buf, ": ");
        ri->http_headers[i].value = skip(buf, "\r\n");
        if (ri->http_headers[i].name[0] == '\0')
            break;
        ri->num_headers = i + 1;
    }
}

static bool_t
is_known_http_method(const char *method)
{
    return (!strcmp(method, "GET") ||
            !strcmp(method, "POST") ||
            !strcmp(method, "HEAD") ||
            !strcmp(method, "PUT") ||
            !strcmp(method, "DELETE"));
}

/*
 * Parse HTTP request, fill in mg_request_info structure.
 */
static bool_t
parse_http_request(char *buf, struct mg_request_info *ri, const struct usa *usa)
{
    char	*http_version;
    int	n, success_code = FALSE;

    ri->request_method = skip(&buf, " ");
    ri->uri = skip(&buf, " ");
    http_version = skip(&buf, "\r\n");

    if (is_known_http_method(ri->request_method) &&
            ri->uri[0] == '/' &&
            sscanf(http_version, "HTTP/%d.%d%n",
                   &ri->http_version_major, &ri->http_version_minor, &n) == 2 &&
            http_version[n] == '\0')
    {
        parse_http_headers(&buf, ri);
        ri->remote_port = ntohs(usa->u.sin.sin_port);
        (void) memcpy(&ri->remote_ip, &usa->u.sin.sin_addr.s_addr, 4);
        ri->remote_ip = ntohl(ri->remote_ip);
        success_code = TRUE;
    }

    return (success_code);
}

/*
 * Keep reading the input (either opened file descriptor fd, or socket sock,
 * or SSL descriptor ssl) into buffer buf, until \r\n\r\n appears in the
 * buffer (which marks the end of HTTP request). Buffer buf may already
 * have some data. The length of the data is stored in nread.
 * Upon every read operation, increase nread by the number of bytes read.
 */
static int
read_request(FILE *fp, SOCKET sock, SSL *ssl, char *buf, int bufsiz, int *nread)
{
    int	n, request_len;

    request_len = 0;
    while (*nread < bufsiz && request_len == 0)
    {
#ifdef _UDT_

        n = pull_udt(fp, sock, ssl, buf + *nread, bufsiz - *nread);
#else
        n = pull(fp, sock, ssl, buf + *nread, bufsiz - *nread);
#endif
        if (n <= 0)
        {
            break;
        }
        else
        {
            *nread += n;
            request_len = get_request_len(buf, (size_t) *nread);
        }
    }

    return (request_len);
}

/*
 * For given directory path, substitute it to valid index file.
 * Return 0 if index file has been found, -1 if not found.
 * If the file is found, it's stats is returned in stp.
 */
static bool_t
substitute_index_file(struct mg_connection *conn,
                      char *path, size_t path_len, struct mgstat *stp)
{
    const char	*list;
    struct mgstat	st;
    struct vec	filename_vec;
    size_t		n;
    bool_t		found;

    n = strlen(path);

    /*
     * The 'path' given to us points to the directory. Remove all trailing
     * directory separator characters from the end of the path, and
     * then append single directory separator character.
     */
    while (n > 0 && IS_DIRSEP_CHAR(path[n - 1]))
        n--;
    path[n] = DIRSEP;

    /*
     * Traverse index files list. For each entry, append it to the given
     * path and see if the file exists. If it exists, break the loop
     */
    lock_option(conn->ctx, OPT_INDEX_FILES);
    list = conn->ctx->options[OPT_INDEX_FILES];
    found = FALSE;

    while ((list = next_option(list, &filename_vec, NULL)) != NULL)
    {

        /* Ignore too long entries that may overflow path buffer */
        if (filename_vec.len > path_len - n)
            continue;

        /* Prepare full path to the index file  */
        (void) mg_strlcpy(path + n + 1,
                          filename_vec.ptr, filename_vec.len + 1);

        /* Does it exist ? */
        if (mg_stat(path, &st) == 0)
        {
            /* Yes it does, break the loop */
            *stp = st;
            found = TRUE;
            break;
        }
    }
    unlock_option(conn->ctx, OPT_INDEX_FILES);

    /* If no index file exists, restore directory path */
    if (found == FALSE)
        path[n] = '\0';

    return (found);
}

static void
remove_callback(struct mg_context *ctx,
                const char *uri_regex, int status_code, bool_t is_auth)
{
    struct callback	*cb;
    int		i;

    for (i = 0; i < ctx->num_callbacks; i++)
    {
        cb = ctx->callbacks + i;
        if ((uri_regex != NULL && cb->uri_regex != NULL &&
                ((is_auth && cb->is_auth) || (!is_auth && !cb->is_auth)) &&
                !strcmp(uri_regex, cb->uri_regex)) || (uri_regex == NULL &&
                                                       (cb->status_code == 0 ||
                                                        cb->status_code == status_code)))
        {
            (void) memmove(cb, cb + 1,
                           (char *) (ctx->callbacks + ctx->num_callbacks) -
                           (char *) (cb + 1));
            break;
        }
    }
}

static void
add_callback(struct mg_context *ctx, const char *uri_regex, int status_code,
             mg_callback_t func, bool_t is_auth, void *user_data)
{
    struct callback	*cb;

    pthread_mutex_lock(&ctx->bind_mutex);
    if (func == NULL)
    {
        remove_callback(ctx, uri_regex, status_code, is_auth);
    }
    else if (ctx->num_callbacks >= (int) ARRAY_SIZE(ctx->callbacks) - 1)
    {
        cry(fc(ctx), "Too many callbacks! Increase MAX_CALLBACKS.");
    }
    else
    {
        cb = &ctx->callbacks[ctx->num_callbacks];
        cb->uri_regex = uri_regex ? mg_strdup(uri_regex) : NULL;
        cb->func = func;
        cb->is_auth = is_auth;
        cb->status_code = status_code;
        cb->user_data = user_data;
        ctx->num_callbacks++;
        DEBUG_TRACE((DEBUG_MGS_PREFIX "%s: uri %s code %d",
                     __func__, uri_regex ? uri_regex : "NULL", status_code));
    }
    pthread_mutex_unlock(&ctx->bind_mutex);
}

void
mg_set_uri_callback(struct mg_context *ctx, const char *uri_regex,
                    mg_callback_t func, void *user_data)
{
    assert(uri_regex != NULL);
    add_callback(ctx, uri_regex, -1, func, FALSE, user_data);
}

void
mg_set_error_callback(struct mg_context *ctx, int error_code,
                      mg_callback_t func, void *user_data)
{
    assert(error_code >= 0 && error_code < 1000);
    add_callback(ctx, NULL, error_code, func, FALSE, user_data);
}

void
mg_set_auth_callback(struct mg_context *ctx, const char *uri_regex,
                     mg_callback_t func, void *user_data)
{
    assert(uri_regex != NULL);
    add_callback(ctx, uri_regex, -1, func, TRUE, user_data);
}

/*
 * Return True if we should reply 304 Not Modified.
 */
static bool_t
is_not_modified(const struct mg_connection *conn, const struct mgstat *stp)
{
    const char *ims = mg_get_header(conn, "If-Modified-Since");
    return (ims != NULL && stp->mtime < date_to_epoch(ims));
}

static bool_t
append_chunk(struct mg_request_info *ri, FILE *fp, const char *buf, int len)
{
    bool_t	ret_code = TRUE;

    if (fp == NULL)
    {
        /* TODO: check for NULL here */
        ri->post_data = (char *) realloc(ri->post_data,
                                         ri->post_data_len + len);
        (void) memcpy(ri->post_data + ri->post_data_len, buf, len);
        ri->post_data_len += len;
    }
    else
#ifdef _UDT_
        if (push_udt(fp, INVALID_SOCKET,
                     NULL, buf, (uint64_t) len) != (uint64_t) len)
        {
#else
        if (push(fp, INVALID_SOCKET,
                 NULL, buf, (uint64_t) len) != (uint64_t) len)
        {
#endif
            ret_code = FALSE;
        }

    return (ret_code);
}

static bool_t
handle_request_body(struct mg_connection *conn, FILE *fp)
{
    struct mg_request_info	*ri = &conn->request_info;
    const char	*expect, *tmp;
    uint64_t	content_len;
    char		buf[BUFSIZ];
    int		to_read, nread, already_read;
    bool_t		success_code = FALSE;

    content_len = get_content_length(conn);
    expect = mg_get_header(conn, "Expect");

    if (content_len == UNKNOWN_CONTENT_LENGTH)
    {
        send_error(conn, 411, "Length Required", "");
    }
    else if (expect != NULL && mg_strcasecmp(expect, "100-continue"))
    {
        send_error(conn, 417, "Expectation Failed", "");
    }
    else
    {
        if (expect != NULL)
            (void) mg_printf(conn, "HTTP/1.1 100 Continue\r\n\r\n");

        already_read = ri->post_data_len;
        assert(already_read >= 0);

        if (content_len <= (uint64_t) already_read)
        {
            ri->post_data_len = (int) content_len;
            /*
             * If fp is NULL, this is embedded mode, and we do not
             * have to do anything: POST data is already there,
             * no need to allocate a buffer and copy it in.
             * If fp != NULL, we need to write the data.
             */
#ifdef _UDT_
            success_code = fp == NULL || (push_udt(fp, INVALID_SOCKET,
                                                   NULL, ri->post_data, content_len) == content_len) ?
                           TRUE : FALSE;
#else
            success_code = fp == NULL || (push(fp, INVALID_SOCKET,
                                               NULL, ri->post_data, content_len) == content_len) ?
                           TRUE : FALSE;
#endif
        }
        else
        {

            if (fp == NULL)
            {
                conn->free_post_data = TRUE;
                tmp = ri->post_data;
                /* +1 in case if already_read == 0 */
                ri->post_data = (char*)malloc(already_read + 1);
                (void) memcpy(ri->post_data, tmp, already_read);
            }
            else
            {
#ifdef _UDT_
                (void) push(fp, INVALID_SOCKET, NULL,
                            ri->post_data, (uint64_t) already_read);
#else
                (void) push(fp, INVALID_SOCKET, NULL,
                            ri->post_data, (uint64_t) already_read);
#endif
            }

            content_len -= already_read;

            while (content_len > 0)
            {
                to_read = sizeof(buf);
                if ((uint64_t) to_read > content_len)
                    to_read = (int) content_len;
#ifdef _UDT_
                nread = pull_udt(NULL, conn->client.sock,
                                 conn->ssl, buf, to_read);
#else
                nread = pull(NULL, conn->client.sock,
                             conn->ssl, buf, to_read);
#endif
                if (nread <= 0)
                    break;
                if (!append_chunk(ri, fp, buf, nread))
                    break;
                content_len -= nread;
            }
            success_code = content_len == 0 ? TRUE : FALSE;
        }

        /* Each error code path in this function must send an error */
        if (success_code != TRUE)
            send_error(conn, 577, http_500_error,
                       "%s", "Error handling body data");
    }

    return (success_code);
}

#if !defined(NO_CGI)

/*
 * This structure helps to create an environment for the spawned CGI program.
 * Environment is an array of "VARIABLE=VALUE\0" ASCIIZ strings,
 * last element must be NULL.
 * However, on Windows there is a requirement that all these VARIABLE=VALUE\0
 * strings must reside in a contiguous buffer. The end of the buffer is
 * marked by two '\0' characters.
 * We satisfy both worlds: we create an envp array (which is vars), all
 * entries are actually pointers inside buf.
 */
struct cgi_env_block
{
    struct mg_connection *conn;
    char	buf[CGI_ENVIRONMENT_SIZE];	/* Environment buffer	*/
    int	len;				/* Space taken		*/
    char	*vars[MAX_CGI_ENVIR_VARS];	/* char **envp		*/
    int	nvars;				/* Number of variables	*/
};

/*
 * Append VARIABLE=VALUE\0 string to the buffer, and add a respective
 * pointer into the vars array.
 */
static char *
addenv(struct cgi_env_block *block, const char *fmt, ...)
{
    int	n, space;
    char	*added;
    va_list	ap;

    /* Calculate how much space is left in the buffer */
    space = sizeof(block->buf) - block->len - 2;
    assert(space >= 0);

    /* Make a pointer to the free space int the buffer */
    added = block->buf + block->len;

    /* Copy VARIABLE=VALUE\0 string into the free space */
    va_start(ap, fmt);
    n = mg_vsnprintf(block->conn, added, (size_t) space, fmt, ap);
    va_end(ap);

    /* Make sure we do not overflow buffer and the envp array */
    if (n > 0 && n < space &&
            block->nvars < (int) ARRAY_SIZE(block->vars) - 2)
    {
        /* Append a pointer to the added string into the envp array */
        block->vars[block->nvars++] = block->buf + block->len;
        /* Bump up used length counter. Include \0 terminator */
        block->len += n + 1;
    }

    return (added);
}

static void
prepare_cgi_environment(struct mg_connection *conn, const char *prog,
                        struct cgi_env_block *blk)
{
    const char	*s, *script_filename, *root;
    struct vec	var_vec;
    char		*p;
    int		i;

    blk->len = blk->nvars = 0;
    blk->conn = conn;

    /* SCRIPT_FILENAME */
    script_filename = prog;
    if ((s = strrchr(prog, '/')) != NULL)
        script_filename = s + 1;

    lock_option(conn->ctx, OPT_ROOT);
    root = conn->ctx->options[OPT_ROOT];
    addenv(blk, "SERVER_NAME=%s", conn->ctx->options[OPT_AUTH_DOMAIN]);
    unlock_option(conn->ctx, OPT_ROOT);

    /* Prepare the environment block */
    addenv(blk, "%s", "GATEWAY_INTERFACE=CGI/1.1");
    addenv(blk, "%s", "SERVER_PROTOCOL=HTTP/1.1");
    addenv(blk, "%s", "REDIRECT_STATUS=200");	/* PHP */
    addenv(blk, "SERVER_PORT=%d", ntohs(conn->client.lsa.u.sin.sin_port));
    addenv(blk, "SERVER_ROOT=%s", root);
    addenv(blk, "DOCUMENT_ROOT=%s", root);
    addenv(blk, "REQUEST_METHOD=%s", conn->request_info.request_method);
    addenv(blk, "REMOTE_ADDR=%s",
           inet_ntoa(conn->client.rsa.u.sin.sin_addr));
    addenv(blk, "REMOTE_PORT=%d", conn->request_info.remote_port);
    addenv(blk, "REQUEST_URI=%s", conn->request_info.uri);
    addenv(blk, "SCRIPT_NAME=%s", prog + strlen(root));
    addenv(blk, "SCRIPT_FILENAME=%s", script_filename);	/* PHP */
    addenv(blk, "PATH_TRANSLATED=%s", prog);
    addenv(blk, "HTTPS=%s", conn->ssl == NULL ? "off" : "on");

    if ((s = mg_get_header(conn, "Content-Type")) != NULL)
        addenv(blk, "CONTENT_TYPE=%s", s);

    if (conn->request_info.query_string != NULL)
        addenv(blk, "QUERY_STRING=%s", conn->request_info.query_string);

    if ((s = mg_get_header(conn, "Content-Length")) != NULL)
        addenv(blk, "CONTENT_LENGTH=%s", s);

    if ((s = getenv("PATH")) != NULL)
        addenv(blk, "PATH=%s", s);

#if defined(_WIN32)
    if ((s = getenv("COMSPEC")) != NULL)
        addenv(blk, "COMSPEC=%s", s);
    if ((s = getenv("SYSTEMROOT")) != NULL)
        addenv(blk, "SYSTEMROOT=%s", s);
#else
    if ((s = getenv("LD_LIBRARY_PATH")) != NULL)
        addenv(blk, "LD_LIBRARY_PATH=%s", s);
#endif /* _WIN32 */

    if ((s = getenv("PERLLIB")) != NULL)
        addenv(blk, "PERLLIB=%s", s);

    if (conn->request_info.remote_user != NULL)
    {
        addenv(blk, "REMOTE_USER=%s", conn->request_info.remote_user);
        addenv(blk, "%s", "AUTH_TYPE=Digest");
    }

    /* Add all headers as HTTP_* variables */
    for (i = 0; i < conn->request_info.num_headers; i++)
    {
        p = addenv(blk, "HTTP_%s=%s",
                   conn->request_info.http_headers[i].name,
                   conn->request_info.http_headers[i].value);

        /* Convert variable name into uppercase, and change - to _ */
        for (; *p != '=' && *p != '\0'; p++)
        {
            if (*p == '-')
                *p = '_';
            *p = (char) toupper(* (unsigned char *) p);
        }
    }

    /* Add user-specified variables */
    lock_option(conn->ctx, OPT_CGI_ENV);
    s = conn->ctx->options[OPT_CGI_ENV];
    while ((s = next_option(s, &var_vec, NULL)) != NULL)
        addenv(blk, "%.*s", var_vec.len, var_vec.ptr);
    unlock_option(conn->ctx, OPT_CGI_ENV);

    blk->vars[blk->nvars++] = NULL;
    blk->buf[blk->len++] = '\0';

    assert(blk->nvars < (int) ARRAY_SIZE(blk->vars));
    assert(blk->len > 0);
    assert(blk->len < (int) sizeof(blk->buf));
}

static void
send_cgi(struct mg_connection *conn, const char *prog)
{
    int			headers_len, data_len, i, n;
    const char		*status;
    char			buf[MAX_REQUEST_SIZE], *pbuf;
    struct mg_request_info	ri;
    struct cgi_env_block	blk;
    char			dir[FILENAME_MAX], *p;
    int			fd_stdin[2], fd_stdout[2];
    FILE			*in, *out;
    pid_tt			pid;

    prepare_cgi_environment(conn, prog, &blk);

    /* CGI must be executed in its own directory */
    (void) mg_snprintf(conn, dir, sizeof(dir), "%s", prog);
    if ((p = strrchr(dir, DIRSEP)) != NULL)
        *p++ = '\0';

    pid = (pid_tt) -1;
    fd_stdin[0] = fd_stdin[1] = fd_stdout[0] = fd_stdout[1] = -1;
    in = out = NULL;

    if (pipe(fd_stdin) != 0 || pipe(fd_stdout) != 0)
    {
        send_error(conn, 500, http_500_error,
                   "Cannot create CGI pipe: %s", strerror(ERRNO));
        goto done;
    }
    else if ((pid = spawn_process(conn, p, blk.buf, blk.vars,
                                  fd_stdin[0], fd_stdout[1], dir)) == (pid_tt) -1)
    {
        goto done;
    }
    else if ((in = fdopen(fd_stdin[1], "wb")) == NULL ||
             (out = fdopen(fd_stdout[0], "rb")) == NULL)
    {
        send_error(conn, 500, http_500_error,
                   "fopen: %s", strerror(ERRNO));
        goto done;
    }

    setbuf(in, NULL);
    setbuf(out, NULL);

    /*
     * spawn_process() must close those!
     * If we don't mark them as closed, close() attempt before
     * return from this function throws an exception on Windows.
     * Windows does not like when closed descriptor is closed again.
     */
    fd_stdin[0] = fd_stdout[1] = -1;

    /* Send POST data to the CGI process if needed */
    if (!strcmp(conn->request_info.request_method, "POST") &&
            !handle_request_body(conn, in))
    {
        goto done;
    }

    /*
     * Now read CGI reply into a buffer. We need to set correct
     * status code, thus we need to see all HTTP headers first.
     * Do not send anything back to client, until we buffer in all
     * HTTP headers.
     */
    data_len = 0;
    headers_len = read_request(out, INVALID_SOCKET, NULL,
                               buf, sizeof(buf), &data_len);
    if (headers_len <= 0)
    {
        send_error(conn, 500, http_500_error,
                   "CGI program sent malformed HTTP headers: [%.*s]",
                   data_len, buf);
        goto done;
    }
    pbuf = buf;
    buf[headers_len - 1] = '\0';
    parse_http_headers(&pbuf, &ri);

    /* Make up and send the status line */
    status = get_header(&ri, "Status");
    conn->request_info.status_code = status == NULL ? 200 : atoi(status);
    (void) mg_printf(conn, "HTTP/1.1 %d OK\r\n",
                     conn->request_info.status_code);

    /* Send headers */
    for (i = 0; i < ri.num_headers; i++)
        (void) mg_printf(conn, "%s: %s\r\n",
                         ri.http_headers[i].name,
                         ri.http_headers[i].value);
    (void) mg_write(conn, "\r\n", 2);

    /* Send chunk of data that may be read after the headers */
    conn->num_bytes_sent += mg_write(conn,
                                     buf + headers_len, data_len - headers_len);

    /*
     * Read the rest of CGI output and send to the client. If read from
     * CGI returns 0, CGI has finished output. If it returns < 0,
     * some read error occured (CGI process terminated unexpectedly?)
     * If write to the client fails, the means client has disconnected
     * unexpectedly.
     * In all such cases, stop data exchange and do cleanup.
     */
    do
    {
#ifdef _UDT_
        n = pull_udt(out, INVALID_SOCKET, NULL, buf, sizeof(buf));
#else
        n = pull(out, INVALID_SOCKET, NULL, buf, sizeof(buf));
#endif
        if (n > 0)
            n = mg_write(conn, buf, n);
        if (n > 0)
            conn->num_bytes_sent += n;
    }
    while (n > 0);

done:
    if (pid != (pid_tt) -1)
        kill(pid, SIGTERM);
    if (fd_stdin[0] != -1)
        (void) close(fd_stdin[0]);
    if (fd_stdout[1] != -1)
        (void) close(fd_stdout[1]);

    if (in != NULL)
        (void) fclose(in);
    else if (fd_stdin[1] != -1)
        (void) close(fd_stdin[1]);

    if (out != NULL)
        (void) fclose(out);
    else if (fd_stdout[0] != -1)
        (void) close(fd_stdout[0]);
}
#endif /* !NO_CGI */

/*
 * For a given PUT path, create all intermediate subdirectories
 * for given path. Return 0 if the path itself is a directory,
 * or -1 on error, 1 if OK.
 */
static int
put_dir(const char *path)
{
    char		buf[FILENAME_MAX];
    const char	*s, *p;
    struct mgstat	st;
    size_t		len;

    for (s = p = path + 2; (p = strchr(s, '/')) != NULL; s = ++p)
    {
        len = p - path;
        assert(len < sizeof(buf));
        (void) memcpy(buf, path, len);
        buf[len] = '\0';

        /* Try to create intermediate directory */
        if (mg_stat(buf, &st) == -1 && mg_mkdir(buf, 0755) != 0)
            return (-1);

        /* Is path itself a directory ? */
        if (p[1] == '\0')
            return (0);
    }

    return (1);
}

static void
put_file(struct mg_connection *conn, const char *path)
{
    struct mgstat	st;
    FILE		*fp;
    int		rc;

    conn->request_info.status_code = mg_stat(path, &st) == 0 ? 200 : 201;

    if (mg_get_header(conn, "Range"))
    {
        send_error(conn, 501, "Not Implemented",
                   "%s", "Range support for PUT requests is not implemented");
    }
    else if ((rc = put_dir(path)) == 0)
    {
        (void) mg_printf(conn, "HTTP/1.1 %d OK\r\n\r\n",
                         conn->request_info.status_code);
    }
    else if (rc == -1)
    {
        send_error(conn, 500, http_500_error,
                   "put_dir(%s): %s", path, strerror(ERRNO));
    }
    else if ((fp = mg_fopen(path, "wb+")) == NULL)
    {
        send_error(conn, 500, http_500_error,
                   "fopen(%s): %s", path, strerror(ERRNO));
    }
    else
    {
        set_close_on_exec(fileno(fp));
        if (handle_request_body(conn, fp))
            (void) mg_printf(conn, "HTTP/1.1 %d OK\r\n\r\n",
                             conn->request_info.status_code);
        (void) fclose(fp);
    }
}

#if !defined(NO_SSI)
static void send_ssi_file(struct mg_connection *, const char *, FILE *, int);

static void
do_ssi_include(struct mg_connection *conn, const char *ssi, char *tag,
               int include_level)
{
    char	file_name[BUFSIZ], path[FILENAME_MAX], *p;
    FILE	*fp;

    /*
     * sscanf() is safe here, since send_ssi_file() also uses buffer
     * of size BUFSIZ to get the tag. So strlen(tag) is always < BUFSIZ.
     */
    if (sscanf(tag, " virtual=\"%[^\"]\"", file_name) == 1)
    {
        /* File name is relative to the webserver root */
        lock_option(conn->ctx, OPT_ROOT);
        (void) mg_snprintf(conn, path, sizeof(path), "%s%c%s",
                           conn->ctx->options[OPT_ROOT], DIRSEP, file_name);
        unlock_option(conn->ctx, OPT_ROOT);
    }
    else if (sscanf(tag, " file=\"%[^\"]\"", file_name) == 1)
    {
        /*
         * File name is relative to the webserver working directory
         * or it is absolute system path
         */
        (void) mg_snprintf(conn, path, sizeof(path), "%s", file_name);
    }
    else if (sscanf(tag, " \"%[^\"]\"", file_name) == 1)
    {
        /* File name is relative to the currect document */
        (void) mg_snprintf(conn, path, sizeof(path), "%s", ssi);
        if ((p = strrchr(path, DIRSEP)) != NULL)
            p[1] = '\0';
        (void) mg_snprintf(conn, path + strlen(path),
                           sizeof(path) - strlen(path), "%s", file_name);
    }
    else
    {
        cry(conn, "Bad SSI #include: [%s]", tag);
        return;
    }

    if ((fp = mg_fopen(path, "rb")) == NULL)
    {
        cry(conn, "Cannot open SSI #include: [%s]: fopen(%s): %s",
            tag, path, strerror(ERRNO));
    }
    else
    {
        set_close_on_exec(fileno(fp));
        if (match_extension(path,
                            conn->ctx->options[OPT_SSI_EXTENSIONS]))
        {
            send_ssi_file(conn, path, fp, include_level + 1);
        }
        else
        {
            send_opened_file_stream(conn, fp,
                                    UNKNOWN_CONTENT_LENGTH);
        }
        (void) fclose(fp);
    }
}

static void
do_ssi_exec(struct mg_connection *conn, char *tag)
{
    char	cmd[BUFSIZ];
    FILE	*fp;

    if (sscanf(tag, " \"%[^\"]\"", cmd) != 1)
    {
        cry(conn, "Bad SSI #exec: [%s]", tag);
    }
    else if ((fp = popen(cmd, "r")) == NULL)
    {
        cry(conn, "Cannot SSI #exec: [%s]: %s", cmd, strerror(ERRNO));
    }
    else
    {
        send_opened_file_stream(conn, fp, UNKNOWN_CONTENT_LENGTH);
        (void) pclose(fp);
    }
}

static void
send_ssi_file(struct mg_connection *conn, const char *path, FILE *fp,
              int include_level)
{
    char	buf[BUFSIZ];
    int	ch, len, in_ssi_tag;

    if (include_level > 10)
    {
        cry(conn, "SSI #include level is too deep (%s)", path);
        return;
    }

    in_ssi_tag = FALSE;
    len = 0;

    while ((ch = fgetc(fp)) != EOF)
    {
        if (in_ssi_tag && ch == '>')
        {
            in_ssi_tag = FALSE;
            buf[len++] = ch & 0xff;
            buf[len] = '\0';
            assert(len <= (int) sizeof(buf));
            if (len < 6 || memcmp(buf, "<!--#", 5) != 0)
            {
                /* Not an SSI tag, pass it */
                (void) mg_write(conn, buf, len);
            }
            else
            {
                if (!memcmp(buf + 5, "include", 7))
                {
                    do_ssi_include(conn, path, buf + 12,
                                   include_level);
                }
                else if (!memcmp(buf + 5, "exec", 4))
                {
                    do_ssi_exec(conn, buf + 9);
                }
                else
                {
                    cry(conn, "%s: unknown SSI "
                        "command: \"%s\"", path, buf);
                }
            }
            len = 0;
        }
        else if (in_ssi_tag)
        {
            if (len == 5 && memcmp(buf, "<!--#", 5) != 0)
            {
                /* Not an SSI tag */
                in_ssi_tag = FALSE;
            }
            else if (len == (int) sizeof(buf) - 2)
            {
                cry(conn, "%s: SSI tag is too large", path);
                len = 0;
            }
            buf[len++] = ch & 0xff;
        }
        else if (ch == '<')
        {
            in_ssi_tag = TRUE;
            if (len > 0)
                (void) mg_write(conn, buf, len);
            len = 0;
            buf[len++] = ch & 0xff;
        }
        else
        {
            buf[len++] = ch & 0xff;
            if (len == (int) sizeof(buf))
            {
                (void) mg_write(conn, buf, len);
                len = 0;
            }
        }
    }

    /* Send the rest of buffered data */
    if (len > 0)
        (void) mg_write(conn, buf, len);

}

static void
send_ssi(struct mg_connection *conn, const char *path)
{
    FILE	*fp;

    if ((fp = mg_fopen(path, "rb")) == NULL)
    {
        send_error(conn, 500, http_500_error,
                   "fopen(%s): %s", path, strerror(ERRNO));
    }
    else
    {
        set_close_on_exec(fileno(fp));
        (void) mg_printf(conn, "%s", "HTTP/1.1 200 OK\r\n"
                         "Content-Type: text/html\r\nConnection: close\r\n\r\n");
        send_ssi_file(conn, path, fp, 0);
        (void) fclose(fp);
    }
}
#endif /* !NO_SSI */

void
mg_authorize(struct mg_connection *conn)
{
    conn->embedded_auth = TRUE;
}

static bool_t
check_embedded_authorization(struct mg_connection *conn)
{
    const struct callback	*cb;
    bool_t			authorized;

    authorized = TRUE;
    cb = find_callback(conn->ctx, TRUE, conn->request_info.uri, -1);

    if (cb != NULL)
    {
        cb->func(conn, &conn->request_info, cb->user_data);
        authorized = conn->embedded_auth;
    }

    return (authorized);
}

/*
 * This is the heart of the Mongoose's logic.
 * This function is called when the request is read, parsed and validated,
 * and Mongoose must decide what action to take: serve a file, or
 * a directory, or call embedded function, etcetera.
 */
static void
analyze_request(struct mg_connection *conn)
{
    struct mg_request_info *ri = &conn->request_info;
    char			path[FILENAME_MAX], *uri = ri->uri;
    struct mgstat		st;
    const struct callback	*cb;

    if ((conn->request_info.query_string = strchr(uri, '?')) != NULL)
        * conn->request_info.query_string++ = '\0';

    (void) url_decode(uri, (int) strlen(uri), uri, strlen(uri) + 1, FALSE);
    remove_double_dots_and_double_slashes(uri);
    convert_uri_to_file_name(conn, uri, path, sizeof(path));

    if (!check_authorization(conn, path))
    {
        send_authorization_request(conn);
    }
    else if (check_embedded_authorization(conn) == FALSE)
    {
        /*
         * Embedded code failed authorization. Do nothing here, since
         * an embedded code must handle this itself by either
         * showing proper error message, or redirecting to some
         * sort of login page, or something else.
         */
    }
    else if ((cb = find_callback(conn->ctx, FALSE, uri, -1)) != NULL)
    {
        if ((strcmp(ri->request_method, "POST") != 0 &&
                strcmp(ri->request_method, "PUT") != 0) ||
                handle_request_body(conn, NULL))
            cb->func(conn, &conn->request_info, cb->user_data);
    }
    else if (strstr(path, PASSWORDS_FILE_NAME))
    {
        /* Do not allow to view passwords files */
        send_error(conn, 403, "Forbidden", "Access Forbidden");
    }
    else if ((!strcmp(ri->request_method, "PUT") ||
              !strcmp(ri->request_method, "DELETE")) &&
             (conn->ctx->options[OPT_AUTH_PUT] == NULL ||
              !is_authorized_for_put(conn)))
    {
        send_authorization_request(conn);
    }
    else if (!strcmp(ri->request_method, "PUT"))
    {
        put_file(conn, path);
    }
    else if (!strcmp(ri->request_method, "DELETE"))
    {
        if (mg_remove(path) == 0)
            send_error(conn, 200, "OK", "");
        else
            send_error(conn, 500, http_500_error,
                       "remove(%s): %s", path, strerror(ERRNO));
    }
    else if (mg_stat(path, &st) != 0)
    {
        send_error(conn, 404, "Not Found", "%s", "File not found");
    }
    else if (st.is_directory && uri[strlen(uri) - 1] != '/')
    {
        (void) mg_printf(conn,
                         "HTTP/1.1 301 Moved Permanently\r\n"
                         "Location: %s/\r\n\r\n", uri);
    }
    else if (st.is_directory &&
             substitute_index_file(conn, path, sizeof(path), &st) == FALSE)
    {
        if (is_true(conn->ctx->options[OPT_DIR_LIST]))
        {
            send_directory(conn, path);
        }
        else
        {
            send_error(conn, 403, "Directory Listing Denied",
                       "Directory listing denied");
        }
#if !defined(NO_CGI)
    }
    else if (match_extension(path,
                             conn->ctx->options[OPT_CGI_EXTENSIONS]))
    {
        if (strcmp(ri->request_method, "POST") &&
                strcmp(ri->request_method, "GET"))
        {
            send_error(conn, 501, "Not Implemented",
                       "Method %s is not implemented", ri->request_method);
        }
        else
        {
            send_cgi(conn, path);
        }
#endif /* NO_CGI */
#if !defined(NO_SSI)
    }
    else if (match_extension(path,
                             conn->ctx->options[OPT_SSI_EXTENSIONS]))
    {
        send_ssi(conn, path);
#endif /* NO_SSI */
    }
    else if (is_not_modified(conn, &st))
    {
        send_error(conn, 304, "Not Modified", "");
    }
    else
    {
        send_file(conn, path, &st);
    }
}

static void
close_all_listening_sockets(struct mg_context *ctx)
{
    int	i;

    for (i = 0; i < ctx->num_listeners; i++)
        (void) closesocket(ctx->listeners[i].sock);
    ctx->num_listeners = 0;
}

static bool_t
set_ports_option(struct mg_context *ctx, const char *list)
{
#ifdef _UDT_
    UDTSOCKET sock;
#else
    SOCKET		sock;
#endif
    int		is_ssl;
    struct vec	vec;
    struct socket	*listener;

    close_all_listening_sockets(ctx);
    assert(ctx->num_listeners == 0);
#ifdef _UDT_
    while ((list = next_option(list, &vec, NULL)) != NULL)
    {

        is_ssl	= vec.ptr[vec.len - 1] == 's' ? TRUE : FALSE;
        listener = ctx->listeners + ctx->num_listeners;

        if (ctx->num_listeners >=
                (int) (ARRAY_SIZE(ctx->listeners) - 1))
        {
            cry(fc(ctx), "%s", "Too many listeninig sockets");
            return (FALSE);
        }
        else if ((sock = mg_open_listening_port_udt(ctx,
                         vec.ptr, &listener->lsa)) == INVALID_SOCKET)
        {
            cry(fc(ctx), "cannot bind to %.*s", vec.len, vec.ptr);
            return (FALSE);
        }
        else if (is_ssl == TRUE && ctx->ssl_ctx == NULL)
        {
            (void) closesocket(sock);
            cry(fc(ctx), "cannot add SSL socket, please specify "
                "-ssl_cert option BEFORE -ports option");
            return (FALSE);
        }
        else
        {
            listener->sock = sock;
            listener->is_ssl = is_ssl;
            ctx->num_listeners++;
        }

    }
#else
    while ((list = next_option(list, &vec, NULL)) != NULL)
    {

        is_ssl	= vec.ptr[vec.len - 1] == 's' ? TRUE : FALSE;
        listener = ctx->listeners + ctx->num_listeners;

        if (ctx->num_listeners >=
                (int) (ARRAY_SIZE(ctx->listeners) - 1))
        {
            cry(fc(ctx), "%s", "Too many listeninig sockets");
            return (FALSE);
        }
        else if ((sock = mg_open_listening_port(ctx,
                                                vec.ptr, &listener->lsa)) == INVALID_SOCKET)
        {
            cry(fc(ctx), "cannot bind to %.*s", vec.len, vec.ptr);
            return (FALSE);
        }
        else if (is_ssl == TRUE && ctx->ssl_ctx == NULL)
        {
            (void) closesocket(sock);
            cry(fc(ctx), "cannot add SSL socket, please specify "
                "-ssl_cert option BEFORE -ports option");
            return (FALSE);
        }
        else
        {
            listener->sock = sock;
            listener->is_ssl = is_ssl;
            ctx->num_listeners++;
        }

    }
#endif
    return (TRUE);
}

static void
log_header(const struct mg_connection *conn, const char *header, FILE *fp)
{
    const char	*header_value;

    if ((header_value = mg_get_header(conn, header)) == NULL)
    {
        (void) fprintf(fp, "%s", " -");
    }
    else
    {
        (void) fprintf(fp, " \"%s\"", header_value);
    }
}

static void
log_access(const struct mg_connection *conn)
{
    const struct mg_request_info *ri;
    char		date[64];

    if (conn->ctx->access_log == NULL)
        return;

    (void) strftime(date, sizeof(date), "%d/%b/%Y:%H:%M:%S %z",
                    localtime(&conn->birth_time));

    ri = &conn->request_info;

    flockfile(conn->ctx->access_log);

    (void) fprintf(conn->ctx->access_log,
                   "%s - %s [%s] \"%s %s HTTP/%d.%d\" %d %" UINT64_FMT "u",
                   inet_ntoa(conn->client.rsa.u.sin.sin_addr),
                   ri->remote_user == NULL ? "-" : ri->remote_user,
                   date,
                   ri->request_method ? ri->request_method : "-",
                   ri->uri ? ri->uri : "-",
                   ri->http_version_major, ri->http_version_minor,
                   conn->request_info.status_code, conn->num_bytes_sent);
    log_header(conn, "Referer", conn->ctx->access_log);
    log_header(conn, "User-Agent", conn->ctx->access_log);
    (void) fputc('\n', conn->ctx->access_log);
    (void) fflush(conn->ctx->access_log);

    funlockfile(conn->ctx->access_log);
}

static bool_t
isbyte(int n)
{
    return (n >= 0 && n <= 255);
}

/*
 * Verify given socket address against the ACL.
 * Return -1 if ACL is malformed, 0 if address is disallowed, 1 if allowed.
 */
static int
check_acl(struct mg_context *ctx, const char *list, const struct usa *usa)
{
    int		a, b, c, d, n, mask, allowed;
    char		flag;
    uint32_t	acl_subnet, acl_mask, remote_ip;
    struct vec	vec;

    (void) memcpy(&remote_ip, &usa->u.sin.sin_addr, sizeof(remote_ip));

    /* If any ACL is set, deny by default */
    allowed = '-';

    while ((list = next_option(list, &vec, NULL)) != NULL)
    {

        mask = 32;

        if (sscanf(vec.ptr, "%c%d.%d.%d.%d%n",
                   &flag, &a, &b, &c, &d, &n) != 5)
        {
            cry(fc(ctx),
                "%s: subnet must be [+|-]x.x.x.x[/x]", __func__);
            return (-1);
        }
        else if (flag != '+' && flag != '-')
        {
            cry(fc(ctx), "%s: flag must be + or -: [%s]",
                __func__, vec.ptr);
            return (-1);
        }
        else if (!isbyte(a)||!isbyte(b)||!isbyte(c)||!isbyte(d))
        {
            cry(fc(ctx),
                "%s: bad ip address: [%s]", __func__, vec.ptr);
            return (-1);
        }
        else if (sscanf(vec.ptr + n, "/%d", &mask) == 0)
        {
            /* Do nothing, no mask specified */
        }
        else if (mask < 0 || mask > 32)
        {
            cry(fc(ctx), "%s: bad subnet mask: %d [%s]",
                __func__, n, vec.ptr);
            return (-1);
        }

        acl_subnet = (a << 24) | (b << 16) | (c << 8) | d;
        acl_mask = mask ? 0xffffffffU << (32 - mask) : 0;

        if (acl_subnet == (ntohl(remote_ip) & acl_mask))
            allowed = flag;
    }

    return (allowed == '+' ? 1 : 0);
}

static void
add_to_set(SOCKET fd, fd_set *set, int *max_fd)
{
    FD_SET(fd, set);
    if (fd > (SOCKET) *max_fd)
        *max_fd = (int) fd;
}

#ifdef _UDT_
static void
add_to_set_udt(UDTSOCKET fd, UDT::UDSET *set, int *max_fd)
{
    UD_SET(fd, set);
    if (fd > (UDTSOCKET) *max_fd)
        *max_fd = (int)fd;
}
#endif
/*
 * Deallocate mongoose context, free up the resources
 */
static void
mg_fini(struct mg_context *ctx)
{
    int	i;

    close_all_listening_sockets(ctx);

    /* Wait until all threads finish */
    (void) pthread_mutex_lock(&ctx->thr_mutex);
    while (ctx->num_threads > 0)
        (void) pthread_cond_wait(&ctx->thr_cond, &ctx->thr_mutex);
    (void) pthread_mutex_unlock(&ctx->thr_mutex);

    /* Deallocate all registered callbacks */
    for (i = 0; i < ctx->num_callbacks; i++)
        if (ctx->callbacks[i].uri_regex != NULL)
            free(ctx->callbacks[i].uri_regex);

    /* Deallocate all options */
    for (i = 0; i < NUM_OPTIONS; i++)
        if (ctx->options[i] != NULL)
            free(ctx->options[i]);

    /* Close log files */
    if (ctx->access_log)
        (void) fclose(ctx->access_log);
    if (ctx->error_log)
        (void) fclose(ctx->error_log);

    /* Deallocate SSL context */
    if (ctx->ssl_ctx)
        SSL_CTX_free(ctx->ssl_ctx);

    /* Deallocate mutexes and condvars */
    for (i = 0; i < NUM_OPTIONS; i++)
        (void) pthread_mutex_destroy(&ctx->opt_mutex[i]);

    (void) pthread_mutex_destroy(&ctx->thr_mutex);
    (void) pthread_mutex_destroy(&ctx->bind_mutex);
    (void) pthread_cond_destroy(&ctx->thr_cond);
    (void) pthread_cond_destroy(&ctx->empty_cond);
    (void) pthread_cond_destroy(&ctx->full_cond);

    /* Signal mg_stop() that we're done */
    ctx->stop_flag = 2;
}

#if !defined(_WIN32)
static bool_t
set_uid_option(struct mg_context *ctx, const char *uid)
{
    struct passwd	*pw;
    int		retval = FALSE;

    if ((pw = getpwnam(uid)) == NULL)
        cry(fc(ctx), "%s: unknown user [%s]", __func__, uid);
    else if (setgid(pw->pw_gid) == -1)
        cry(fc(ctx), "%s: setgid(%s): %s",
            __func__, uid, strerror(errno));
    else if (setuid(pw->pw_uid) == -1)
        cry(fc(ctx), "%s: setuid(%s): %s",
            __func__, uid, strerror(errno));
    else
        retval = TRUE;

    return (retval);
}
#endif /* !_WIN32 */

#if !defined(NO_SSL)
void
mg_set_ssl_password_callback(struct mg_context *ctx, mg_spcb_t func)
{
    ctx->ssl_password_callback = func;
}

static pthread_mutex_t *ssl_mutexes;

static void
ssl_locking_callback(int mode, int mutex_num, const char *file, int line)
{
    line = 0;	/* Unused */
    file = NULL;	/* Unused */

    if (mode & CRYPTO_LOCK)
        (void) pthread_mutex_lock(&ssl_mutexes[mutex_num]);
    else
        (void) pthread_mutex_unlock(&ssl_mutexes[mutex_num]);
}

static unsigned long
ssl_id_callback(void)
{
    return ((unsigned long) pthread_self());
}

static bool_t
load_dll(struct mg_context *ctx, const char *dll_name, struct ssl_func *sw)
{
    union {void *p;
        void (*fp)(void);
    } u;
    void		*dll_handle;
    struct ssl_func	*fp;

    if ((dll_handle = dlopen(dll_name, RTLD_LAZY)) == NULL)
    {
        cry(fc(ctx), "%s: cannot load %s", __func__, dll_name);
        return (FALSE);
    }

    for (fp = sw; fp->name != NULL; fp++)
    {
#ifdef _WIN32
        /* GetProcAddress() returns pointer to function */
        u.fp = (void (*)(void)) dlsym(dll_handle, fp->name);
#else
        /*
        * dlsym() on UNIX returns void *.
        * ISO C forbids casts of data pointers to function
        * pointers. We need to use a union to make a cast.
        */
        u.p = dlsym(dll_handle, fp->name);
#endif /* _WIN32 */
        if (u.fp == NULL)
        {
            cry(fc(ctx), "%s: cannot find %s", __func__, fp->name);
            return (FALSE);
        }
        else
        {
            fp->ptr = u.fp;
        }
    }

    return (TRUE);
}

/*
 * Dynamically load SSL library. Set up ctx->ssl_ctx pointer.
 */
static bool_t
set_ssl_option(struct mg_context *ctx, const char *pem)
{
    SSL_CTX		*CTX;
    int		i, size, retval = FALSE;

    if (load_dll(ctx, SSL_LIB, ssl_sw) == FALSE ||
            load_dll(ctx, CRYPTO_LIB, crypto_sw) == FALSE)
        return (FALSE);

    /* Initialize SSL crap */
    SSL_library_init();

    if ((CTX = SSL_CTX_new(SSLv23_server_method())) == NULL)
        cry(fc(ctx), "SSL_CTX_new error");
    else if (ctx->ssl_password_callback != NULL)
        SSL_CTX_set_default_passwd_cb(CTX, ctx->ssl_password_callback);

    if (CTX != NULL && SSL_CTX_use_certificate_file(
                CTX, pem, SSL_FILETYPE_PEM) == 0)
        cry(fc(ctx), "%s: cannot open %s", __func__, pem);
    else if (CTX != NULL && SSL_CTX_use_PrivateKey_file(
                 CTX, pem, SSL_FILETYPE_PEM) == 0)
        cry(fc(ctx), "%s: cannot open %s", NULL, pem);
    else
        retval = TRUE;

    /*
     * Initialize locking callbacks, needed for thread safety.
     * http://www.openssl.org/support/faq.html#PROG1
     */
    size = sizeof(pthread_mutex_t) * CRYPTO_num_locks();
    if ((ssl_mutexes = (pthread_mutex_t *) malloc(size)) == NULL)
    {
        cry(fc(ctx), "%s: cannot allocate mutexes", __func__);
        return (FALSE);
    }

    for (i = 0; i < CRYPTO_num_locks(); i++)
        pthread_mutex_init(&ssl_mutexes[i], NULL);

    CRYPTO_set_locking_callback(&ssl_locking_callback);
    CRYPTO_set_id_callback(&ssl_id_callback);

    /* Done with everything. Save the context. */
    ctx->ssl_ctx = CTX;

    return (retval);
}
#endif /* !NO_SSL */

static bool_t
open_log_file(struct mg_context *ctx, FILE **fpp, const char *path)
{
    bool_t	retval = TRUE;

    if (*fpp != NULL)
        (void) fclose(*fpp);

    if (path == NULL)
    {
        *fpp = NULL;
    }
    else if ((*fpp = mg_fopen(path, "a")) == NULL)
    {
        cry(fc(ctx), "%s(%s): %s", __func__, path, strerror(errno));
        retval = FALSE;
    }
    else
    {
        set_close_on_exec(fileno(*fpp));
    }

    return (retval);
}

static bool_t
set_alog_option(struct mg_context *ctx, const char *path)
{
    return (open_log_file(ctx, &ctx->access_log, path));
}

static bool_t
set_elog_option(struct mg_context *ctx, const char *path)
{
    return (open_log_file(ctx, &ctx->error_log, path));
}

static bool_t
set_gpass_option(struct mg_context *ctx, const char *path)
{
    struct mgstat	mgstat;
    ctx = NULL;
    return (mg_stat(path, &mgstat) == 0);
}

static bool_t
set_max_threads_option(struct mg_context *ctx, const char *str)
{
    ctx->max_threads = atoi(str);
    return (TRUE);
}

static bool_t
set_acl_option(struct mg_context *ctx, const char *acl)
{
    struct usa	fake;

    return (check_acl(ctx, acl, &fake) != -1);
}

static void admin_page(struct mg_connection *,
                       const struct mg_request_info *, void *);
static bool_t
set_admin_uri_option(struct mg_context *ctx, const char *uri)
{
    mg_set_uri_callback(ctx, uri, &admin_page, NULL);
    return (TRUE);
}

/*
 * Check if the comma-separated list of options has a format of key-value
 * pairs: "k1=v1,k2=v2". Return FALSE if any entry has invalid key or value.
 */
static bool_t
set_kv_list_option(struct mg_context *ctx, const char *str)
{
    const char	*list;
    struct vec	key, value;

    list = str;
    while ((list = next_option(list, &key, &value)) != NULL)
        if (key.len == 0 || value.len == 0)
        {
            cry(fc(ctx), "Invalid list specified: [%s], "
                "expecting key1=value1,key2=value2,...", str);
            return (FALSE);
        }

    return (TRUE);
}

static const struct mg_option known_options[] =
{
    {"root", "\tWeb root directory", NULL, OPT_ROOT, NULL
    },
    {"index_files",	"Index files", "index.html,index.htm,index.cgi",
     OPT_INDEX_FILES, NULL
    },
#if !defined(NO_SSL)
    {"ssl_cert", "SSL certificate file", NULL,
     OPT_SSL_CERTIFICATE, &set_ssl_option
    },
#endif /* !NO_SSL */
    {"ports", "Listening ports", NULL,
     OPT_PORTS, &set_ports_option
    },
    {"dir_list", "Directory listing", "yes",
     OPT_DIR_LIST, NULL
    },
    {"protect", "URI to htpasswd mapping", NULL,
     OPT_PROTECT, &set_kv_list_option
    },
#if !defined(NO_CGI)
    {"cgi_ext", "CGI extensions", ".cgi,.pl,.php",
     OPT_CGI_EXTENSIONS, NULL
    },
    {"cgi_interp", "CGI interpreter to use with all CGI scripts", NULL,
     OPT_CGI_INTERPRETER, NULL
    },
    {"cgi_env", "Custom CGI enviroment variables", NULL,
     OPT_CGI_ENV, &set_kv_list_option
    },
#endif /* NO_CGI */
    {"ssi_ext", "SSI extensions", ".shtml,.shtm",
     OPT_SSI_EXTENSIONS, NULL
    },
    {"auth_realm", "Authentication domain name", "mydomain.com",
     OPT_AUTH_DOMAIN, NULL
    },
    {"auth_gpass", "Global passwords file", NULL,
     OPT_AUTH_GPASSWD, &set_gpass_option
    },
    {"auth_PUT", "PUT,DELETE auth file", NULL,
     OPT_AUTH_PUT, NULL
    },
#if !defined(_WIN32)
    {"uid", "\tRun as user", NULL, OPT_UID, &set_uid_option
    },
#endif /* !_WIN32 */
    {"access_log", "Access log file", NULL,
     OPT_ACCESS_LOG, &set_alog_option
    },
    {"error_log", "Error log file", NULL,
     OPT_ERROR_LOG, &set_elog_option
    },
    {"aliases", "Path=URI mappings", NULL,
     OPT_ALIASES, &set_kv_list_option
    },
    {"admin_uri", "Administration page URI", NULL,
     OPT_ADMIN_URI, &set_admin_uri_option
    },
    {"acl", "\tAllow/deny IP addresses/subnets", NULL,
     OPT_ACL, &set_acl_option
    },
    {"max_threads", "Maximum simultaneous threads to spawn", "100",
     OPT_MAX_THREADS, &set_max_threads_option
    },
    {"idle_time", "Time in seconds connection stays idle", "10",
     OPT_IDLE_TIME, NULL
    },
    {"mime_types", "Comma separated list of ext=mime_type pairs", NULL,
     OPT_MIME_TYPES, &set_kv_list_option
    },
    {NULL, NULL, NULL, 0, NULL}
};

static const struct mg_option *
            find_opt(const char *opt_name)
{
    int	i;

    for (i = 0; known_options[i].name != NULL; i++)
        if (!strcmp(opt_name, known_options[i].name))
            return (known_options + i);

    return (NULL);
}

int
mg_set_option(struct mg_context *ctx, const char *opt, const char *val)
{
    const struct mg_option	*option;
    int			i, retval;

    DEBUG_TRACE((DEBUG_MGS_PREFIX "%s: [%s]->[%s]", __func__, opt, val));
    if (opt != NULL && (option = find_opt(opt)) != NULL)
    {
        i = (int) (option - known_options);
        lock_option(ctx, i);

        if (option->setter != NULL)
            retval = option->setter(ctx, val);
        else
            retval = TRUE;

        /* Free old value if any */
        if (ctx->options[option->index] != NULL)
            free(ctx->options[option->index]);

        /* Set new option value */
        ctx->options[option->index] = val ? mg_strdup(val) : NULL;
        unlock_option(ctx, i);

        if (retval == FALSE)
            cry(fc(ctx), "%s(%s): failure", __func__, opt);
    }
    else
    {
        cry(fc(ctx), "%s: No such option: [%s]", __func__, opt);
        retval = -1;
    }

    return (retval);
}

void
mg_show_usage_string(FILE *fp)
{
    const struct mg_option	*o;

    (void) fprintf(stderr,
                   "Mongoose version %s (c) Sergey Lyubka\n"
                   "usage: mongoose [options] [config_file]\n", mg_version());

    fprintf(fp, "  -A <htpasswd_file> <realm> <user> <passwd>\n");

    for (o = known_options; o->name != NULL; o++)
    {
        (void) fprintf(fp, "  -%s\t%s", o->name, o->description);
        if (o->default_value != NULL)
            fprintf(fp, " (default: \"%s\")", o->default_value);
        fputc('\n', fp);
    }
}

const char *
mg_get_option(const struct mg_context *ctx, const char *option_name)
{
    const struct mg_option	*option;

    if ((option = find_opt(option_name)) != NULL)
        return (ctx->options[option->index]);
    else
        return (NULL);
}

static void
admin_page(struct mg_connection *conn, const struct mg_request_info *ri,
           void *user_data)
{
    const struct mg_option	*option;
    const char		*option_name, *option_value;

    user_data = NULL; /* Unused */

    (void) mg_printf(conn,
                     "HTTP/1.1 200 OK\r\n"
                     "Content-Type: text/html\r\n\r\n"
                     "<html><body><h1>Mongoose v. %s</h1>", mg_version());

    if (!strcmp(ri->request_method, "POST"))
    {
        option_name = mg_get_var(conn, "o");
        option_value = mg_get_var(conn, "v");
        if (mg_set_option(conn->ctx,
                          option_name, option_value) == -1)
        {
            (void) mg_printf(conn,
                             "<p style=\"background: red\">Error setting "
                             "option \"%s\"</p>",
                             option_name ? option_name : "(null)");
        }
        else
        {
            (void) mg_printf(conn,
                             "<p style=\"color: green\">Saved: %s=%s</p>",
                             option_name, option_value ? option_value : "NULL");
        }
    }

    /* Print table with all options */
    (void) mg_printf(conn, "%s", "<table border=\"1\""
                     "<tr><th>Option</th><th>Description</th>"
                     "<th colspan=2>Value</th></tr>");

    for (option = known_options; option->name != NULL; option++)
    {
        option_value = mg_get_option(conn->ctx, option->name);
        if (option_value == NULL)
            option_value = "";
        (void) mg_printf(conn,
                         "<form method=post><tr><td>%s</td><td>%s</td>"
                         "<input type=hidden name=o value='%s'>"
                         "<td><input type=text name=v value='%s'></td>"
                         "<td><input type=submit value=save></td></form></tr>",
                         option->name, option->description,
                         option->name, option_value);
    }

    (void) mg_printf(conn, "%s", "</table></body></html>");
}

static void
reset_per_request_attributes(struct mg_connection *conn)
{
    if (conn->request_info.remote_user != NULL)
    {
        free((void *) conn->request_info.remote_user);
        conn->request_info.remote_user = NULL;
    }
    if (conn->free_post_data && conn->request_info.post_data != NULL)
    {
        free((void *) conn->request_info.post_data);
        conn->request_info.post_data = NULL;
    }
}

static void
close_socket_gracefully(struct mg_connection *conn, SOCKET sock)
{
    char	buf[BUFSIZ];
    int	n;

    /* Send FIN to the client */
    (void) shutdown(sock, SHUT_WR);
    set_non_blocking_mode(conn, sock);

    /*
     * Read and discard pending data. If we do not do that and close the
     * socket, the data in the send buffer may be discarded. This
     * behaviour is seen on Windows, when client keeps sending data
     * when server decide to close the connection; then when client
     * does recv() it gets no data back.
     */
    do
    {
#ifdef _UDT_
        n = pull_udt(NULL, sock, NULL, buf, sizeof(buf));
#else
        n = pull(NULL, sock, NULL, buf, sizeof(buf));
#endif
    }
    while (n > 0);

    /* Now we know that our FIN is ACK-ed, safe to close */
    (void) closesocket(sock);
}

static void
close_connection(struct mg_connection *conn)
{
    reset_per_request_attributes(conn);

    if (conn->ssl)
        SSL_free(conn->ssl);

    if (conn->client.sock != INVALID_SOCKET)
        close_socket_gracefully(conn, conn->client.sock);
}

static void
reset_connection_attributes(struct mg_connection *conn)
{
    reset_per_request_attributes(conn);
    conn->free_post_data = FALSE;
    conn->request_info.status_code = -1;
    conn->num_bytes_sent = 0;
    (void) memset(&conn->request_info, 0, sizeof(conn->request_info));
}

static void
shift_to_next(struct mg_connection *conn, char *buf, int req_len, int *nread)
{
    uint64_t	cl;
    int		over_len, body_len;

    cl = get_content_length(conn);
    over_len = *nread - req_len;
    assert(over_len >= 0);

    if (cl == UNKNOWN_CONTENT_LENGTH)
    {
        body_len = 0;
    }
    else if (cl < (uint64_t) over_len)
    {
        body_len = (int) cl;
    }
    else
    {
        body_len = over_len;
    }

    *nread -= req_len + body_len;
    (void) memmove(buf, buf + req_len + body_len, *nread);
}

static void
process_new_connection(struct mg_connection *conn)
{
    struct mg_request_info *ri = &conn->request_info;
    char	buf[MAX_REQUEST_SIZE];
    int	request_len, nread;

    nread = 0;
    reset_connection_attributes(conn);

    /* If next request is not pipelined, read it in */
    if ((request_len = get_request_len(buf, (size_t) nread)) == 0)
        request_len = read_request(NULL, conn->client.sock,
                                   conn->ssl, buf, sizeof(buf), &nread);
    assert(nread >= request_len);

    if (request_len <= 0)
        return;	/* Remote end closed the connection */

    /* 0-terminate the request: parse_request uses sscanf */
    buf[request_len - 1] = '\0';

    if (parse_http_request(buf, ri, &conn->client.rsa))
    {
        if (ri->http_version_major != 1 ||
                (ri->http_version_major == 1 &&
                 (ri->http_version_minor < 0 ||
                  ri->http_version_minor > 1)))
        {
            send_error(conn, 505,
                       "HTTP version not supported",
                       "%s", "Weird HTTP version");
            log_access(conn);
        }
        else
        {
            ri->post_data = buf + request_len;
            ri->post_data_len = nread - request_len;
            conn->birth_time = time(NULL);
            analyze_request(conn);
            log_access(conn);
            shift_to_next(conn, buf, request_len, &nread);
        }
    }
    else
    {
        /* Do not put garbage in the access log */
        send_error(conn, 400, "Bad Request",
                   "Can not parse request: [%.*s]", nread, buf);
    }

}

/*
 * Worker threads take accepted socket from the queue
 */
static bool_t
get_socket(struct mg_context *ctx, struct socket *sp)
{
    struct timespec	ts;

    (void) pthread_mutex_lock(&ctx->thr_mutex);
    DEBUG_TRACE((DEBUG_MGS_PREFIX "%s: thread %p: going idle",
                 __func__, (void *) pthread_self()));

    /* If the queue is empty, wait. We're idle at this point. */
    ctx->num_idle++;
    while (ctx->sq_head == ctx->sq_tail)
    {
        ts.tv_nsec = 0;
        ts.tv_sec = time(NULL) + atoi(ctx->options[OPT_IDLE_TIME]) + 1;
        if (pthread_cond_timedwait(&ctx->empty_cond,
                                   &ctx->thr_mutex, &ts) != 0)
        {
            /* Timeout! release the mutex and return */
            (void) pthread_mutex_unlock(&ctx->thr_mutex);
            return (FALSE);
        }
    }
    assert(ctx->sq_head > ctx->sq_tail);

    /* We're going busy now: got a socket to process! */
    ctx->num_idle--;

    /* Copy socket from the queue and increment tail */
    *sp = ctx->queue[ctx->sq_tail % ARRAY_SIZE(ctx->queue)];
    ctx->sq_tail++;
    DEBUG_TRACE((DEBUG_MGS_PREFIX
                 "%s: thread %p grabbed socket %d, going busy",
                 __func__, (void *) pthread_self(), sp->sock));

    /* Wrap pointers if needed */
    while (ctx->sq_tail > (int) ARRAY_SIZE(ctx->queue))
    {
        ctx->sq_tail -= ARRAY_SIZE(ctx->queue);
        ctx->sq_head -= ARRAY_SIZE(ctx->queue);
    }

    pthread_cond_signal(&ctx->full_cond);
    (void) pthread_mutex_unlock(&ctx->thr_mutex);

    return (TRUE);
}

static void
worker_thread(struct mg_context *ctx)
{
    struct mg_connection	conn;


    DEBUG_TRACE((DEBUG_MGS_PREFIX "%s: thread %p starting",
                 __func__, (void *) pthread_self()));

    (void) memset(&conn, 0, sizeof(conn));

    while (get_socket(ctx, &conn.client) == TRUE)
    {
        conn.birth_time = time(NULL);
        conn.ctx = ctx;

        if (conn.client.is_ssl &&
                (conn.ssl = SSL_new(conn.ctx->ssl_ctx)) == NULL)
        {
            cry(&conn, "%s: SSL_new: %d", __func__, ERRNO);
        }
        else if (conn.client.is_ssl &&
                 SSL_set_fd(conn.ssl, conn.client.sock) != 1)
        {
            cry(&conn, "%s: SSL_set_fd: %d", __func__, ERRNO);
        }
        else if (conn.client.is_ssl && SSL_accept(conn.ssl) != 1)
        {
            cry(&conn, "%s: SSL handshake error", __func__);
        }
        else
        {
            process_new_connection(&conn);
        }

        close_connection(&conn);
    }

    /* Signal master that we're done with connection and exiting */
    pthread_mutex_lock(&conn.ctx->thr_mutex);
    conn.ctx->num_threads--;
    conn.ctx->num_idle--;
    pthread_cond_signal(&conn.ctx->thr_cond);
    assert(conn.ctx->num_threads >= 0);
    pthread_mutex_unlock(&conn.ctx->thr_mutex);

    DEBUG_TRACE((DEBUG_MGS_PREFIX "%s: thread %p exiting",
                 __func__, (void *) pthread_self()));
}

/*
 * Master thread adds accepted socket to a queue
 */
static void
put_socket(struct mg_context *ctx, const struct socket *sp)
{
    (void) pthread_mutex_lock(&ctx->thr_mutex);

    /* If the queue is full, wait */
    while (ctx->sq_head - ctx->sq_tail >= (int) ARRAY_SIZE(ctx->queue))
        (void) pthread_cond_wait(&ctx->full_cond, &ctx->thr_mutex);
    assert(ctx->sq_head - ctx->sq_tail < (int) ARRAY_SIZE(ctx->queue));

    /* Copy socket to the queue and increment head */
    ctx->queue[ctx->sq_head % ARRAY_SIZE(ctx->queue)] = *sp;
    ctx->sq_head++;
    DEBUG_TRACE((DEBUG_MGS_PREFIX "%s: queued socket %d",
                 __func__, sp->sock));

    /* If there are no idle threads, start one */
    if (ctx->num_idle == 0 && ctx->num_threads < ctx->max_threads)
    {
        if (start_thread(ctx,
                         (mg_thread_func_t) worker_thread, ctx) != 0)
            cry(fc(ctx), "Cannot start thread: %d", ERRNO);
        else
            ctx->num_threads++;
    }

    pthread_cond_signal(&ctx->empty_cond);
    (void) pthread_mutex_unlock(&ctx->thr_mutex);
}

static void
accept_new_connection(const struct socket *listener, struct mg_context *ctx)
{
    struct socket		accepted;
    printf("accept a new connection \n");
    accepted.rsa.len = sizeof(accepted.rsa.u.sin);
    accepted.lsa = listener->lsa;
#ifdef _UDT_

    if ((accepted.sock = UDT::accept(listener->sock,
                                     &accepted.rsa.u.sa, &accepted.rsa.len)) == INVALID_SOCKET)
#else
    if ((accepted.sock = accept(listener->sock,
                                &accepted.rsa.u.sa, &accepted.rsa.len)) == INVALID_SOCKET)
#endif
        return;

    lock_option(ctx, OPT_ACL);
    if (ctx->options[OPT_ACL] != NULL &&
            !check_acl(ctx, ctx->options[OPT_ACL], &accepted.rsa))
    {
        cry(fc(ctx), "%s: %s is not allowed to connect",
            __func__, inet_ntoa(accepted.rsa.u.sin.sin_addr));
        (void) closesocket(accepted.sock);
        unlock_option(ctx, OPT_ACL);
        return;
    }
    unlock_option(ctx, OPT_ACL);

    /* Put accepted socket structure into the queue */
    DEBUG_TRACE((DEBUG_MGS_PREFIX "%s: accepted socket %d",
                 __func__, accepted.sock));
    accepted.is_ssl = listener->is_ssl;
    put_socket(ctx, &accepted);
}

static void
master_thread(struct mg_context *ctx)
{
#ifdef _UDT_
    UDT::UDSET read_set;
#else
    fd_set		read_set;
#endif
    struct timeval	tv;
    int		i, max_fd;

    while (ctx->stop_flag == 0)
    {
#ifdef _UDT_

        max_fd = -1;
        //UD_ZERO(&read_set);
        /* Add listening sockets to the read set */
        lock_option(ctx, OPT_PORTS);
        for (i = 0; i < ctx->num_listeners; i++)
            add_to_set_udt(ctx->listeners[i].sock, &read_set, &max_fd);
#else

        max_fd = -1;

        /* Add listening sockets to the read set */
        lock_option(ctx, OPT_PORTS);
        for (i = 0; i < ctx->num_listeners; i++)
            add_to_set(ctx->listeners[i].sock, &read_set, &max_fd);
#endif

        unlock_option(ctx, OPT_PORTS);

        tv.tv_sec = 1;
        tv.tv_usec = 0;
#ifdef _UDT_
        if (UDT::ERROR == UDT::select(max_fd + 1, &read_set, NULL, NULL, &tv))
        {
#else
        if (select(max_fd + 1, &read_set, NULL, NULL, &tv) < 0)
        {
#endif
#ifdef _WIN32
            /*
             * On windows, if read_set and write_set are empty,
             * select() returns "Invalid parameter" error
             * (at least on my Windows XP Pro). So in this case,
             * we sleep here.
             */
            sleep(1);
#endif /* _WIN32 */
        }
        else
        {

            lock_option(ctx, OPT_PORTS);
            for (i = 0; i < ctx->num_listeners; i++)
#ifdef _UDT_
                if (UD_ISSET(ctx->listeners[i].sock, &read_set))
#else
                if (FD_ISSET(ctx->listeners[i].sock, &read_set))
#endif

                    accept_new_connection(
                        ctx->listeners + i, ctx);
            unlock_option(ctx, OPT_PORTS);
        }
    }

    /* Stop signal received: somebody called mg_stop. Quit. */
    mg_fini(ctx);
}

void
mg_stop(struct mg_context *ctx)
{
    ctx->stop_flag = 1;

    /* Wait until mg_fini() stops */
    while (ctx->stop_flag != 2)
        (void) sleep(1);

    assert(ctx->num_threads == 0);
    free(ctx);

#if defined(_WIN32)
    (void) WSACleanup();
#endif /* _WIN32 */
}

struct mg_context *
            mg_start(void)
{
    struct mg_context	*ctx;
    const struct mg_option	*option;
    char			web_root[FILENAME_MAX];
    int			i;

#if defined(_WIN32)
    WSADATA data;
    WSAStartup(MAKEWORD(2,2), &data);
#endif /* _WIN32 */

    if ((ctx = (struct mg_context *) calloc(1, sizeof(*ctx))) == NULL)
    {
        cry(fc(ctx), "cannot allocate mongoose context");
        return (NULL);
    }

    ctx->error_log = stderr;
    mg_set_log_callback(ctx, builtin_error_log);

    /* Initialize options. First pass: set default option values */
    for (option = known_options; option->name != NULL; option++)
        ctx->options[option->index] = option->default_value == NULL ?
                                      NULL : mg_strdup(option->default_value);

    /* Call setter functions */
    for (option = known_options; option->name != NULL; option++)
        if (option->setter != NULL &&
                ctx->options[option->index] != NULL)
            if (option->setter(ctx,
                               ctx->options[option->index]) == FALSE)
            {
                mg_fini(ctx);
                return (NULL);
            }

    /* Initial document root is set to current working directory */
    if (ctx->options[OPT_ROOT] == NULL)
    {
        if (mg_getcwd(web_root, sizeof(web_root)) == NULL)
        {
            cry(fc(ctx), "%s: getcwd: %s",
                __func__, strerror(errno));
            mg_strlcpy(web_root, ".", sizeof(web_root));
        }
        ctx->options[OPT_ROOT] = mg_strdup(web_root);
    }

    DEBUG_TRACE((DEBUG_MGS_PREFIX "%s: root [%s]",
                 __func__, ctx->options[OPT_ROOT]));

#if !defined(_WIN32)
    /*
     * Ignore SIGPIPE signal, so if browser cancels the request, it
     * won't kill the whole process.
     */
    (void) signal(SIGPIPE, SIG_IGN);
#endif /* _WIN32 */

    /* Initialize options mutexes */
    for (i = 0; i < NUM_OPTIONS; i++)
        (void) pthread_mutex_init(&ctx->opt_mutex[i], NULL);

    (void) pthread_mutex_init(&ctx->thr_mutex, NULL);
    (void) pthread_mutex_init(&ctx->bind_mutex, NULL);
    (void) pthread_cond_init(&ctx->thr_cond, NULL);
    (void) pthread_cond_init(&ctx->empty_cond, NULL);
    (void) pthread_cond_init(&ctx->full_cond, NULL);

    /* Start master (listening) thread */
    start_thread(ctx, (mg_thread_func_t) master_thread, ctx);

    return (ctx);
}
